DEVELOPMENT ANTHROPOLOGY IN ACTION

 

 

 "INDIGENOUS PLANT PROTECTION IN YEMEN"

 

Study Commissioned by the

Yemeni German Plant Protection Project (GTZ)

for the Ministry of Agriculture and Water Resources (MAWR)

 

by

 

Daniel Martin Varisco

Abdul Rahman Dubaie

Muhammad Jazm

Muhammad Mahyub

Abd al-Wali al-Khuleidi

 

1992

 

Far too many giant projects in developing countries

costing huge sums have failed dismally and have caused

serious ecological problems because they lacked

sufficient understanding of traditional agriculture.

(Thurston 1992:1)

 

socdmv@hofstra.edu

 

 

CONTENTS

 

Executive Summary

List of Abbreviations

Transliteration

1. Introduction

1.1 Objectives and Scope of Study

1.2 Project Rationale

1.3 Project Methodology

1.4 Future Research and Application of Results

2. The Relevance of Indigenous Knowledge for Plant Protection

2.1 Sustainable Production as a Priority

2.2 Plant Protection and Sustainable Crop Production Systems

2.3 Integrated Pest Management for Yemen

3. Indigenous Agricultural Knowledge in Yemen

3.1 General

3.2 Textual Sources

3.3 Traditional Practices

3.4 Summary

4. Traditional Plant Protection Practices in Yemen

4.1 General

4.2 Major Pests and Diseases in Traditional Agriculture

4.2.1 Animal Pests

4.2.2 Plant Pests

4.2.3 Diseases

4.3 Range of Plant Protection Measures

4.3.1 Direct Intervention

4.3.1.1 Biological Control

4.3.1.1.1 Animal

4.3.1.1.2 Botanical

4.3.1.2 Soil/Natural Substance Application

4.3.1.3 Water Application (rain, irrigation, etc.)

4.3.1.4 Smoke/Heat Application

4.3.1.5 Manual Removal

4.3.1.6 Protective Devices

4.3.2 Planting Techniques

4.3.2.1 Timing

4.3.2.2 Location (microclimate, depth of planting, type of soil)

4.3.2.3 Crop Density

4.3.2.4 Care of Plant

4.3.2.5 Tillage Technique

4.3.2.6 Transplanting/Grafting

4.3.2.7 Crop Sequence, Rotation, Use of Fallow

4.3.2.8 Interplanting

4.3.2.9 Preparation of Seed

4.3.2.10 Fire

4.3.3 Crop Variety

4.4 Crop Storage

4.5 Case Study: Date Palms (nakhl) in Yemen

4.6 Summary

5. Recommendations

5.1 General

5.2 Recommendations for IPM and Institutionalized

Collection of Indigenous Protection Practice Data

5.2.1 General

5.2.2 Research Methodology

5.2.3 Coordination with International Organizations

5.3 Outline for a Research Project on Traditional Date Palms

Bibliography

Annex A. Data Base

---

List of Abbreviations

 

 

AREA BF CGIAR CH CIKARD DAM DLRC FAO GDPP HUM IBPGR ICARDA ICRISAT IPM L. MAWR MM r SA UNDP v YGPPP

Agricultural Research and Extension Authority Bughyat al-fallâhîn Consultative Group in International Agricultural Research Chaudhary and Revri (1983) Center for Indigenous Knowledge for Agriculture and Rural Development al-Damîrî (N.D.) Documentation and Learning Resource Center Food and Agriculture Organization General Department of Plant Protection Humiari (1982) International Board for Plant Genetic Resources International Centre for Agricultural Research in Dry Areas International Crops Research Institute for the Semi-Arid Tropics Integrated Pest Management Latin (scientific name) Ministry of Agriculture and Water Resources Milh al-Malâha recto (front of folio) Sâlihîya and al-'Amd (1984) United Nations Development Programme verso (back of folio) YGPPP Yemeni German Plant Protection Project

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Transliteration

 

The transliteration of Arabic terminology in the original report follows the system of the International Journal of Middle Eastern Studies, published in Cambridge, England. [For this html version, it has not been possible to designate proper transliteration of consonants.]

 

Executive Summary

 

The objective of this report is to identify the range of indigenous practices of plant or crop protection in Yemen in order to develop appropriate recommendations for Integrated Pest Management (IPM) in the country's development program. The ultimate goal of an IPM program is sustainable and affordable crop protection which is within the capabilities of farmers and does not harm people or the environment. To the extent that farmers already practice viable methods of traditional crop protection, these need to be understood and encouraged in the development process.

 

Traditional methods of plant protection, both direct and indirect, have largely been ignored in agricultural research within Yemen's development program. There has been no assessment of the relevance of traditional protection methods in Yemeni agriculture. These methods need to be documented in context by scientific methods in order to determine those practices which remain beneficial under modern farming systems. The understanding of indigenous farmer practices is an important prerequisite for developing an effective national program of IPM. A major part of this effort should be coordination with the country's extension service in order to help extension agents communicate more effectively with farmers and encourage those existing practices which contribute to plant protection.

 

Traditional agriculture in Yemen was by and large oriented toward sustainable production with a combination of practices which reduced or eliminated pest infestation and diseases. The study of almanacs and agricultural texts from medieval Yemen, as well as relevant ethnographic data, indicates that such aspects as timing of planting, location and type of soil, use of fertilizer or mulch, tillage and crop care practices, crop density, use of shade, and rotation can be relevant to control of pests and crop diseases. Although details still exist on most of these aspects, the preventive value in crop protection is often forgotten by contemporary farmers. Many farmers now rely exclusively on the application of chemicals for crop protection and have abandoned effective protection methods of the past. There are viable organic and traditional methods, more economical than chemical applications, that can be immediately applied by Yemeni farmers.

 

This study documents several direct methods of plant protection. One of the major practices is a form of biological control in which a predatory ant (qa's) is brought in and placed near date flowers or fruit in order to eat larvae and moths which infest dates. This method is described in a 13th century agricultural text by al-Malik al-Ashraf 'Umar of Rasulid Yemen and continues to the present day in the Tihama and areas south of Ta'izz (such as Wadi al-Barakânî). In the Hadramawt sesame oil is applied to the flowering branches at the time of pollenation in order to protect these from disease; this is a practice also documented in the medieval texts. Several examples were documented of trap plants being placed near a crop in order to ward off harmful insects. These includes barley, colocynth, garlic, onion, Nerium oleander, Ricinus communis (L.) and Calotropis procera. More examples of medieval botanical control are discussed in the medieval agricultural treatises. There are also non-biological mechanisms, such as spraying with dirt, dousing with water, use of smoke or heat, use of protective devices and manual removal of infected parts.

 

This report includes analysis of medieval and later Yemeni texts with relevant information on traditional agriculture, a review of the literature and fieldwork in several regions of the country. The research team consisted of an anthropologist, historian/folklorist, botanist, range ecologist and entomologist. Interviews were conducted with farmers in the Sanaa basin, Tihama, Ta'izz region and Hadramawt, as well as information from the agricultural research station of al-Kawd near Aden. The information has been placed in a computerized data base for ease of access and future modification for research use.

 

The computer base provided with this report is presented as a starting point for future research on indigenous plant protection methods, their relevance to the current development context, and eventual development of communication messages for extension services. It is important that a wide range of specialists examine the data and contribute to the ongoing analysis. Where possible, comments have been made in this report on the scientific viability of certain practices. The purpose of this report is to document traditional practices, but their mere existence does not prove that they are viable or should be encouraged. Many of the practices noted in this report require further analysis and controlled experimentation before they can be recommended to farmers in modern farming systems.

 

Effective IPM requires the integration of sound and proven protection methods within existing farming systems in combination with new inputs and practices. The point is not to deny the relevance of chemical applications, an important component in most modern farming systems, but to find appropriate alternative forms of pest and disease management that reduce the need for expensive and potentially harmful pesticide use. An important preliminary step in any IPM program must be a thorough understanding of the indigenous farming systems before changes are introduced. It is precisely this kind of information which has not been documented in sufficient detail for development planning. Chapter Three of this report describes the range of traditional agricultural knowledge in Yemen. Chapter Four discusses the relevant information on crop protection in Yemen's past. Many of these practices continue, but this knowledge is rapidly disappearing.

 

Recommendations for future action, including the collection of farmer knowledge useful for developing IPM, are provided in Chapter Five. The major recommendations are:

• Systematic documentation of indigenous cultivation and protection techniques in seasonal context. It is recommended that the YGPPP work closely with AREA in developing targeted research on such issues as:

• the range of traditional production practices for date palms in Yemen;

• he use of natural flora in crop protection, especially Calotropis procera, Ricinus communis, onion, garlic, and other plants noted in the report (including potential use in herbal sprays);

• economically viable ways of increasing the amount of manure, mulch and other organic materials used in farming systems;

• the role of the ant (qa's) as biological control of date pests in areas of Yemen where it is not currently used (e.g., the development of commercial ant farms);

• the role of weed identification as an indicator of soil conditions;

• traditional ways in which farmers determine plant health by the state of leaves, etc.;

• determination of viable non-chemical applications (ash, lime, diatomaceous earth. etc.) for crop protection;

• determination of appropriate local planting times based on environmental as well as economic considerations.

• The YGPPP should develop guidelines for the MAWR that emphasize the range of suitable cultivation practices which result in sustainable production as a basis for developing an IPM program at the national level.

• The YGPPP and AREA should jointly develop a manual for Yemeni farmers on how to prevent, reduce or treat common pest and disease problems in Yemen using viable traditional practices and other organic or non-chemical methods recommended elsewhere.

• The YGPPP should develop a computerized base of information on pests and plant diseases in Yemen based on the extensive research that has already been conducted. This report includes a sample computer base developed for the MacIntosh.

• It is recommended that the YGPPP in conjunction with AREA develop links with international organizations concerned with sustainable production and crop production.

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1. Introduction

 

1.1 Objectives and Scope of Study

 

The objective of this project is to identify the range of indigenous or traditional practices of plant or crop protection in Yemen in order to develop appropriate recommendations for Integrated Pest Management (IPM) in the country's development program. The idea is to reduce reliance on chemical applications and build on the sustainable production systems of Yemen's past. While pesticides, herbicides and fungicides will continue to be an important part of farming systems in Yemen, it is important to look for suitable alternative forms of crop protection. This report includes analysis of medieval and later Yemeni texts with relevant information on traditional agricultural practices, a review of the available ethnographic literature and fieldwork in three regions of the country. Attention has been paid to documentation of sources and Arabic terminology in order to facilitate further study. The basic data have been placed in an initial computerized data base for ease of access and future research use.

 

The focus of the study is on traditional methods of pest and disease control in use before the introduction of chemical pesticides, herbicides and fungicides. Only those crops which were traditionally grown in Yemen are examined here, although some of the methods described would be relevant to recently introduced crops. The main issue is to understand the range of techniques used by Yemeni farmers for sustainable production of agricultural crops. A number of direct eradication techniques are described, but this study also identifies techniques and combinations of practices which contribute to overall plant protection and minimal environmental degradation. No attempt is made to analyze traditional farming systems per se, but only to the extent needed for a contextual understanding of plant protection methods.

 

It must be stressed that this is a preliminary study to begin the process of data collection and analysis of indigenous plant protection practices. The overall process requires skills of ethnographers or rural sociologists, historians, botanists, entomologists, and relevant agricultural specialists (plant pathology, agronomy, extension, marketing, etc.) and should be coordinated at the national level. The aim is not to document traditional methods as folklore, but to adapt successful plant protection measures to the ongoing development program in the Ministry of Agriculture and Water Resources (MAWR). It is ultimately a matter of applied research to ensure sustainable production systems in Yemen's currently overstressed environment.

 

1.2 Project Rationale

 

There is a rich tradition of both rainfed and irrigated agriculture in Yemen stemming back at least 3000 years. Despite the presence of reasonably good textual documentation and the continued practice of many traditional methods, virtually none of Yemen's indigenous agricultural knowledge has been applied within the development program. During the past three decades, the development process in north and south has focused on new crop varieties, imported technology and modern farming practices adapted to developed countries. While the goals of this process have been laudable, the methods need to be reassessed in response to the current environmental crisis facing Yemen, such as declining water tables, deforestation, destabilization of terrace systems and a wide range of environmental damage.

 

The key issue in Yemen's present and future development is the sustainability of its agricultural systems (Varisco 1991b). One issue that affects all these systems, both irrigated and rainfed, is plant or crop protection. Crops need to be protected from pests, diseases and natural elements. It is clear from a wide range of experience in both developing and developed countries that reliance on chemical pesticides and related applications does not afford protection on a sustainable basis, either economically or environmentally. Thus, there has been a renewed interest in returning sustainable, mostly organic, methods used in the past. While some of the interest in organic farming has not been scientific in scope, there is a growing awareness among agronomists that traditional farming systems can yield effective practices for today (Thurston 1992).

 

Ironically, Yemen appears to be faced with more pest and disease problems after almost three decades of development than it had under the traditional farming systems of the past. In his visit during 1919 to the Aden Protectorate, Heald (in Ingrams 1936:59) wrote: "Excepting for the caterpillar attacking the young millet [sorghum] and tobacco, the crops were remarkably free from pest and disease; I carefully searched for stem borer in the millet [sorghum] but could find none, and also for the scale in the few citrus trees." Similarly, the medieval sources do not indicate major pest problems, apart from such natural disasters as locust swarms.

 

There are a number of reasons as to why Yemen may have more pest problems today than it did in the past. First, many new crops have been introduced into Yemen and some of these are more vulnerable to diseases or pests. Tomatos probably entered during the last Ottoman period in the 19th century. Potatoes were introduced into the highlands of the Aden Protectorate in 1939 (Keen 1946:10). Second, there has been increased reliance on chemical pesticides and related applications which have killed beneficial insects as well as the targeted pests. The first pesticides appear to have been introduced into North Yemen during the 1930s and perhaps earlier in the south by the British. Third, many traditional protection methods have been altered or stopped so that the preventive approach of the past has been largely abandoned.

 

Farmers in Yemen were able to control pests and diseases in the past to a certain extent based on generations of experience for each local environmental context. While there is no statistical data base on which to evaluate the past effectiveness of past protection measures, there is qualitative evidence of methods which contribute to overall sustainability. Certain crop varieties, especially in the case of sorghum, are well adapted to local environmental conditions and are more resistant to disease or pest problems than recently introduced varieties. While the overall context of agriculture has changed dramatically in recent years, it is important to assess the effectiveness of past crop protection measures in Yemen. There are several reasons for such an effort:

(1) The recent shift to tubewell irrigation and more vulnerable new crop varieties has created a growing dependence on pesticides and fungicides, yet many farmers do not know how to safely apply these and do not have adequate access to the proper pesticides in key seasons.

Insufficient knowledge and improper application compromises the effective use of chemicals (cf. FAO 1991:4:7). Thus, many (if not most) farmers are faced with greater pest problems than under traditional management systems.

(2) The growing dependence on imported pesticides has resulted in a decline in the practice of traditional crop management which contributed in the past to sustainable production of crops. Some farmers have abandoned sound and proven crop protection practices of the past, because they think that chemical applications can solve all problems. However, many disease and pest problems can be mitigated to a great extent through proper cultivation methods rather than chemical treatment (FAO 1991:4:7-8).

(3) A number of farmers have little choice but to continue farming in traditional ways with existing crop varieties. Their production is endangered by pest and disease problems resulting from newly introduced varieties and different management practices elsewhere. It is unreasonable to assume that all farmers will automatically be able to adopt new systems of production with all the necessary inputs.

(4) Past uses of biological control or crop management practices in Yemen have continuing value in the development process because they promote sustainable control over certain kinds of pests and diseases. There are several local plant species in Yemen which have demonstrated effectiveness in pest control. Some of these species are listed in a recent study that documents some 2400 plant species useful in plant protection worldwide (Grainge and Ahmed 1988).

(5) Indigenous agricultural knowledge in the various ecological regions of Yemen is rapidly disappearing as older generations pass on and in the near future this knowledge may no longer be available. This represents not only a loss to Yemen's intellectual heritage, but a potential loss of information relevant for resolving present and future agricultural and environmental problems. The loss of indigenous knowledge on agriculture and sustainable use of the environment is

occurring around the world (Thurston 1992:4).

 

1.3 Project Methodology

 

This project combines textual, ethnographic and scientific analyses with a focus on indigenous knowledge relevant to plant protection and pest management. The project was divided into three phases:

• During Phase I a preliminary study was made of the relevant textual sources in order to document the available information according to plant or crop, pest and disease. This information has been placed in a data base program (Filemaker Pro on the MacIntosh) for ease of access and further study.

• During Phase II fieldwork was conducted among farmers in four distinct ecological regions of Yemen: the central highlands near Sanaa with low rainfall, the southern highlands near Ta'izz with moderate rainfall, Wadi Hadramawt, and coastal spate systems in the Tihâma. This documentation was entered onto the computer program in English.

• In Phase III the information obtained in Phases I and II was initially analyzed in cooperation with technical experts and relevant agricultural specialists in order to identify appropriate protection methods for adaptation to the modern development context of IPM in Yemen.

 

The research team consisted of five individuals. Dr. Daniel Martin Varisco (Hofstra University), an ecological anthropologist with extensive experience in Yemen, coordinated the project and conducted the bulk of the textual analysis in Phase III. Mr. Muhammad Jazm made a preliminary survey of the regions to be studied and assisted in the analysis of medieval sources and ethnographic documentation. Dr. Abdul Rahman Dubaie (Associate Professor of Botany at Sanaa University) assisted in the identification of plants and collection of ethno-botanical information from Yemeni farmers. Mr. Abd al-Wali al-Khuleidi (AREA, Dept. of Forestry, Ta'izz) assisted in botanical study in the Ta'izz area and the Hadramawt. Mr. Muhammad Mahyub (MAWR, GDPP) collected insect specimens and conducted interviews with farmers on local pest problems.

 

The data collected in the project study have been entered into a computerized data base for easy cross-referencing and future updating. The computer data will be provided to the YGPPP for its use and distribution to other concerned organizations, such as the MAWR Documentation Center, AREA, FAO and UNDP. This final report describes the results of the project and provides an initial hard copy of the data base. Recommendations are provided for future initiatives in IPM and extension outreach on plant protection.

 

At the conclusion of the fieldwork, a seminar was conducted (in Arabic) under the sponsorship of the YGPPP on the results of the project and recommendations for IPM in Yemen. This included discussion by Varisco, Jazm and Dubaie on traditional protection techniques and their relevance, as well as an open panel discussion by ministry personnel and interested parties. In addition a lecture on the project results was given in English at the American Institute for Yemeni Studies.

 

1.4 Future Research and Application of Results

 

This project has identified a range of practices which may be beneficial in resolving pest and disease problems for traditional crops. The collection of relevant indigenous knowledge on this subject is difficult for several reasons:

1.Many farmers have abandoned traditional crops or methods and now rely almost exclusively on pesticides and recent innovations. The older generations have forgotten much of the relevant information, due to lack of practical use of many older methods. The younger generations do not have the depth of knowledge about the local environment and past sustainable practices.

2. Many of the pests and diseases must be examined as they occur, but this varies according to season. Only over the long term could a project piece together the detailed information on traditional practices. An outline for a pilot project on date palms is included in this report (section 5.3).

3. Some farmers assume that traditional methods are old-fashioned and are reluctant to discuss these with individuals they perceive to be agricultural experts or ministry personnel. In order to obtain detailed information, it is necessary to build up longer-term relationships with the farmers to be interviewed.

4. Most agricultural experts and personnel, both foreign and Yemeni, do not have the technical training to collect traditional farmer knowledge. Thus, they often misunderstand the purpose of a practice, fail to see it in the broader context, or assume farmers are ignorant. The use of formal questionnaires is also problematic, because this tends to impose categories rather than eliciting the farmer's way of thinking.

 

In order to properly understand protection methods in practice, it would be useful to tap into the existing expertise and contacts of extension agents. Extension agents are in continual contact with farmers and are often aware of the benefits of certain traditional practices. A successful research program should include methods for obtaining information from extension agents. This information needs to be studied by resident technical experts (e.g., in AREA, YGPPP, Sanaa University, specific projects) in order to determine which practices are scientifically sound and which are not. Then the information can be elaborated in communication packages for future extension messages. It is important that such research be coordinated by an appropriate agency, such as AREA, to avoid the continual duplication of research efforts and the failure to utilize existing information in obscure reports.

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2. The Relevance of Indigenous Knowledge for Plant Protection

 

2.1 Sustainable Production as a Priority

 

Over the course of about three millennia Yemen became known as a country rich in agricultural products. The mere presence of the country's thousands upon thousands of carefully crafted terraces indicates the substantial investment of previous generations, especially in rainfed cultivation and water harvesting. Medieval and later agricultural texts, as well as ethnographic data, reveal that Yemeni farmers were quite knowledgeable about the environment. By and large the traditional farming systems resulted in minimal environmental damage. Indeed, farmers were usually practical conservationists who knew that their livelihood depended on careful management of local resources.

 

Agricultural development in Yemen over the past three decades has been oriented towards maximising economic returns. To this end the focus has been on developing efficient tubewell irrigation systems, utilization of mechanization and new crop varieties. It is now clear, however, that Yemen's natural resource base cannot sustain increased tubewell irrigation, nor has mechanized farming proved to be as efficient in practice as assumed. While economic factors will obviously continue to shape the overall agricultural development policy, it is necessary to give equal attention to revitalization of traditional sustainable production systems, especially on rainfed and flood-irrigated lands. The point is not to return to marginal production of the past, but to build on the existing knowledge which still has value. It is essential to combine economic goals with conservation of the country's limited land and water resources.

 

The prioritization of sustainable production for the country's agricultural program does not involve a simplistic choice between modern technology and traditional methods. No one can seriously advocate a return to labor-intensive and subsistence production systems of the past. However, it is necessary to be realistic about Yemen's agricultural development rather than offer dubious predictions of future returns. In order to effectively transfer new technology, methods and crop varieties, socioeconomic realities and variations in existing environmental resources must be taken into account. Any introduced change automatically affects the balance of the ecosystem as a whole, and this can lead to economic losses as well as environmental damage. Evaluations of agricultural development projects around the world indicate that well-intended changes can actually harm the environment and reduce the economic viability of farmers over the long run.

 

Just as one should not introduce changes blindly, so it is counter-productive to ignore existing farmer practices in the development process. This is especially true for Yemen, where the majority of farmers continue to farm in a largely traditional manner on rainfed land. There is at present little documentation of the traditional farming systems in Yemen, especially in terms of which practices are sound and sustainable. Documentation of indigenous practices would provide baseline data needed for shaping agricultural programs within the limits of the country's natural resource base. If one can understand how a particular sustainable production system worked in the past or in existing traditions, it will be easier to develop more complex sustainable systems in the future.

 

The lack of priority for sustainable production systems in Yemen's previous agricultural development process has both a direct and an indirect impact. The direct impact is major environmental degradation of terraced land, open forest and water supply. The environmental issue has intruded itself as a major priority in recent years. The indirect impact is future economic loss due to destruction of the natural resource base and loss of investment in tubewell irrigation systems when groundwater is locally depleted. As has been the case the world over, the lack of a viable resource base in the rural areas will force more families to migrate to the urban areas, which are already overcrowded, for a livelihood. All of this creates an additional economic and social burden on an already strained society in transition.

 

2.2 Plant Protection and Sustainable Crop Production Systems

 

In the past several years it has become apparent that the so-called "Green Revolution", brought about by a simple formula of improved technology and modern methods of production, has been an illusion for many developing countries. While there have been short-term gains in agricultural production, in many cases the newly created systems have proven not to be sustainable. The essential problem is that success was measured in the past almost exclusively in economic terms. Thus, the goal of most agricultural projects has been to increase yield and make farmers wealthier. The success of a farming system needs to be measured not only by immediate economic returns, but by the ability to sustain productivity over the long run and by its social consequences. For farming to be a practical livelihood for families, there is no choice but to farm within the constraints of the environment, natural and socio-economic.

 

The control of pests and diseases in agriculture parallels the development of human health care. Whereas traditional systems in both cases emphasized preventive measures, the tendency now is to attempt to eradicate a specific pest or disease with a "cure". The promotion of pesticides, herbicides and fungicides, despite the obvious short-term benefits, has unfortunately given the false impression that a particular application can solve the pest or disease problem. In fact, the dependence on chemical solutions may encourage the growth of more resistant pests while at the same time destroying beneficial insects and natural predators of pests. For example, all mite pests have been created through pesticide use (World Bank 1991:8). When farmers abandon traditional practices, which were oriented to prevent pest infestation to the extent possible, in the name of progress the whole production system can become more vulnerable to pests and diseases.

 

Assuming that land and water are available, the main concern of any farmer is how to successfully produce a crop. In traditional farming systems farmers were usually cautious and sought to minimize risk rather than gamble on maximizing yields. In such traditional farming systems crop protection was by and large preventive. In looking at such systems, it is difficult to isolate a particular practice as the solution to a pest infestation or disease, although direct eradication measures are sometimes encountered. The key to understanding traditional plant protection is the combination of techniques used in interrelation of seemingly distinct activities. Farmers may not always be aware that a set of practices in a traditional farming system is beneficial for crop protection. Yet, when practices are changed, there is often a noticeable increase in pests and diseases. Most farmers in Yemen complain that pest problems are greater now than in the past, even though pesticides are generally available. This is not because the pesticides are ineffective, if properly applied, but because practices that helped hold populations of pests in check in the past have now been altered.

 

In the United States, which has for years been the world's leader in agricultural expertise, there has been a shift back toward sustainable production systems of the past. This has given rise to a focus on organic farming in order to lessen environmental and health risks, and programs of pest management that reduce reliance on chemical applications. What began as a non-conformist movement has now become mainstream to a large extent. Unfortunately, the message given in developing countries has been that traditional practices are invariably out-of-date and must be abandoned in favor of new and improved technology from the developed countries. It is only recently that attention has shifted to the effectiveness of traditional methods of pest and disease control in local contexts. In a major review of such traditional measures, Thurston (1992:1) at Cornell University concludes that "it is time to reexamine the potential for traditional agriculture to contribute to an improved, sustainable 'modern agriculture'."

 

2.3 Integrated Pest Management for Yemen

 

The most effective approach to plant protection in all countries is one that emphasizes Integrated Pest Management (IPM). This essentially means a broad-based approach to controlling crop pests and diseases rather than relying on chemical applications as the primary focus. The idea is to suppress pests and avoid pest attacks in a way which combines a range of sustainable crop production methods and minimizes damage to the environment or human health. In many cases it is a matter of restoring the natural predator-prey balance that may be disrupted when chemicals destroy beneficial insects and organisms. The idea is not to rely solely on an easy quick-fix solution of chemical applications, but to use pesticides as a last resort (World Bank 1991:10).

 

The application of chemical pesticides, herbicides, fungicides, etc. necessarily alters the local environment. While this may be expedient in certain cases, such interference with the natural cycle should be kept to a minimum. The problem is that in most cases pesticides are applied as a first resort, rather than looking for other, less harmful ways of controlling pests and diseases. Chemical applications are never sustainable, because they must be repeated and may have adverse effects on the local environment. Some of the major negative effects of use and misuse of chemical pesticides include:

• Health. Over a decade ago it was estimated that 100,000 to 400,000 deaths were caused by chemical poisoning from crop protection worldwide (Dover 1985:2). The negative health

impact of pesticide use in developing countries has been documented by Bull (1982). In Yemen it is common to see chemicals being applied by farmers without proper protective clothing. While this may or may not result in immediate health consequences, it can be harmful to health over the long run. Consumers may also not properly clean crop produce before eating it. In the case of Yemen, the harmful effects of chewing sprayed qât (Catha edulis) have been described by Ghashm and Mujâhid (1984).

• Beneficial Insects. Many pesticides are indiscriminate and kill beneficial insects as well as harmful pests. This can disrupt the natural prey-predator balance that generally holds harmful pests in check. It may also interfere with pollenation of crops and natural flora.

• Pollution of groundwater and soils. Along with chemical fertilizers, buildup of chemical residues can interfere with natural organic processes in soils. Residues have also been detected in drinking groundwater, produce, wildlife and human tissues. In addition to problems resulting application in fields, leakage from storage containers can represent a major pollution hazard. Yemen currently has 270 tons of unusable pesticides in storage; these are in urgent need of disposal.

• Promotes Resistant Strains of Pests. One of the major problems in areas where chemical pesticides have been relied upon is that resistant strains of pests often require new chemical solutions. In order to regain control of pests, farmers used higher doses in a virtual "pesticide treadmill" which in some cases caused the virtual collapse of agricultural production (Kiss and Meerman 1991:4).

• Kills bees. This can be a problem in Yemen, where bee hives are often placed near tree crops, such as date palms. There may also be contamination of local honey supply. Honey production has fallen in Egypt since the 1960s and this has been attributed to the effect of insecticides (Matthews 1990:16).

 

Integrated Pest Management cannot be imported verbatim from another country or context. It is not a technology that can be plugged in and run anywhere. Instead, "IPM should be viewed as a strategy and an approach to developing technologies" (Kiss and Meerman 1991:5). There has been a great deal of inappropriate transfer of technology by experts from temperate regions to countries in the tropics and arid zones, where appropriate methods in one context are not appropriate (cf. Thurston 1992:4-8). Effective IPM requires the integration of sound and proven protection methods within existing systems in combination with new inputs and practices. Thus, the a critical part of any IPM program must be a thorough understanding of the indigenous farming systems. This is best achieved with the active participation of farmers in the research process (World Bank 1991:12).

 

It is precisely this kind of information which has not been documented in sufficient detail for development planning in Yemen. Chapter Three of this reports describes briefly the range of traditional agricultural knowledge in Yemen. Chapter Four discusses the relevant information on crop protection in Yemen's past. Recommendations for future action, including the collection of farmer knowledge useful for developing IPM, are provided in Chapter Five.

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3. Indigenous Agricultural Knowledge in Yemen

 

3.1 General

 

Indigenous or traditional agricultural knowledge includes the range of information on which farmers, consciously or unconsciously, base their production systems (cf. Brokensha et al. 1980, Warren et al. 1989, 1991). The term "indigenous" refers to knowledge that is locally based rather than recently imported. Others use the more generic term "traditional" in the sense of practices not informed by modern scientific knowledge and farming systems. In this report the terms are used interchangeably to indicate local farmer knowledge before the agricultural development programs in Yemen's recent past. Much of this information is practical, based on personal experience of the farmer or generations of experience in a certain environmental context. The body of traditional knowledge is continually changing; it is not static and fixed by any means. To say that a farming system is traditional is only to say what it looks like at the time it is being studied. Unfortunately, it is very difficult to determine the historical depth of traditional practices where documentation on the past is lacking or insufficient.

 

Traditional farmers are unable to communicate their practices and experience in scientific terms. Thus, it is assumed by many experts that traditional farmer knowledge is suspect and not a proper subject for development planning (cf. Howes and Chambers 1980). As a result, most development projects are designed without taking into consideration the effectiveness of traditional practices. It is assumed that traditional systems must be modernized and transformed from scratch. Since traditional farmers do not describe their practices in terms that an expert can relate to, it is important for detailed study of indigenous practices and farmers' beliefs. The goal should be to separate what is sound and practical from what is mere folklore or based on misguided beliefs. For example, the fact that a farmer believes that his crops grow because of some magic or prayer, does not mean that other practices are not sound and practical. The relevance of indigenous knowledge should not be prejudged because of the farmer's lack of education and training.

 

Indigenous or traditional knowledge is usually specific to a site or community. A good example of this is the relevance of an agricultural calendar. In the past farmers in Yemen timed their plantings not by almanacs or written schedules but by local observations of star risings and settings, the position of the sun's shadow and observable changes in the seasonal round (e.g., bird migration, appearance of certain insects or plants, etc). In the highland valley of al-Ahjur, for example, farmers planted different varieties of sorghum according to a local shadow scheme (Varisco 1985:62-62). The early morning shadow of a mountain peak was cast on the western slope of the valley. This followed a regular procession north to south based on the angle of the sun at that time of year. In effect, this became a natural clock in which the shadow would reach a certain landmark (large tree or big rock) at the same time each year. The precise details of the shadow scheme would not be relevant outside of the local community, although the principle was applied throughout Yemen in other sites (cf. Serjeant 1974a:31). The same is true for local star calendars which are based on observations of stars in a given locality. These star calendars can rarely be applied outside of a specific context or local region without becoming arbitrary grids (Varisco 1992). What is ultimately important is not the particular star observed in a given season, but how the farmer was able to define a planting time that would provide a productive crop given the constraints of rain and floods and the menace of pests and diseases.

 

Ethnographic study over an extended period of time of traditional farming systems indicates that local farmers have detailed practical knowledge of their local environment. Most practices are not arbitrary, even if particular farmers may not know why they do them. In traditional systems that have proven sustainability the experience of generations of farmers in the local environment shapes a wide range of practices that in some way contribute to crop productivity and protection. It is important to examine the range of practices in traditional systems, because these are the key to sustainability. Very seldom can one identify a particular eradication measure in crop protection, because the system is often designed to prevent or minimize pest and disease problems through a number of indirect methods.

 

This section describes the range of sources available for understanding indigenous farming practices in Yemen. This information is provided as a base for further research and as general background for the detailed look at indigenous practices of plant protection. Special attention has been given to terminology, which is an important component in documentation of ethnographic data and folklore. This is especially true for Yemen, where the nuances of technical terms are not clear from the literal meanings. Given the historical sources available, it is possible to better understand how terms are used today in a specific context and to appreciate variable meanings for both terms and practices. The terminology is also important for designing appropriate extension messages for the variety of farming contexts in Yemen.

 

3.2 Textual Sources

 

Yemen has a rich heritage of historical, scientific and literary texts . While there are occasional references to the region's agriculture in some of these texts, only a few provide details useful for reconstructing the agricultural system in the past. The most important sources are agricultural and botanical texts, many of which were written during the period of the Rasulid sultans between the 13th and 15th centuries A.D. The Rasulid period was the zenith of Yemen's political and intellectual achievements in the medieval period. Through the major port of Aden Yemen had commercial and trading links with Egypt and Africa to the west and Iraq, India and China to the east. There was also a rapid interchange of information on the sciences of the day. There are at least three general agricultural treatises from the scholarly Rasulid sultans themselves, about eight agricultural almanacs and several sources which focus on tax and economic aspects of crop production in Rasulid Yemen (see Varisco 1989c for a list of the texts and their location).

 

The earliest extant agricultural text in Yemen was written by al-Malik al-Ashraf 'Umar towards the end of the 13th century A.D. This is Milh al-malâha fî ma'rifat al-filâha (The Knowledge of Elegance in the Science of Agriculture), which has been partially edited by Muhammad Jâzm (1985) and later by 'Abd Allâh Mujâhid (1987), although the latter edition is unreliable. This same sultan wrote an important agricultural almanac for the year A.D. 1271, which has been edited and translated by Varisco (in press). The works of this Yemeni sultan provide a detailed look at the crops and rare plants cultivated in Yemen. Information is provided on the agricultural cycle for the major crops and specific cultivation methods. Only a limited amount of the information relates to direct forms of pest control; these are discussed in the appropriate sections of this report.

 

The other major Rasulid agricultural text is by al-Malik al-Afdal al-'Abbâs, who died in A.D. 1376. This is the Bughyat al-fallâhîn f al-ashjâr al-muthmira wa-al-rayâhîn (Desirable Practices of Farmers for Flowering Trees and Aromatic Plants), which was first described by Meyerhof (1944). Prof. R. B. Serjeant (Cambridge, emeritus) is preparing an edition of the Arabic text; he previously translated the chapter on grain crops (Serjeant 1974a). This text exists in at least four extant manuscripts (Varisco 1989c: 151-152), the most important of which is in Cairo. There are undoubtedly other copies in Yemen as well. The Bughya is arranged in sixteen chapters, as follows:

1. Types of Land and their Quality

2. Fertilizer (Manure)

3. Water Sources

4. Selection and Clearing of Land for Cultivation

5. Agricultural Seasons and Activities

6. Grains

7. Various Legumes (qatânî)

8. Vegetables (buqûl and khadrawât)

9. Spices and Herbs

10. Aromatic Plants

11. Flowering Trees

12. Pruning of Trees

13. Grafting of Trees

14. Properties of Various Plants

15. Repelling of Plant Pests.

16. Medicinal Plants.

 

This treatise provides an extraordinary window through which to view Yemeni agricultural practices over five hundred years ago. The classification of eleven types of soils draws on earlier texts, but includes information on Yemen as well. There is a detailed discussion of the different types of manure and their uses, as noted below in section 4.2.2. The fourth chapter of al-Afdal's treatise discusses how to choose and prepare the soil for crops. One of the items of advice is to examine the type of plants growing on the soil and see if they are the type that grow in wadi valleys and moist areas. If this is the case, the land has promise. In preparing the land, the text notes, it is first necessary to level it, so that the water will run evenly to all parts of the plots. This includes use of a leveler, known locally in Yemen as a maharr. Then, depending on the soil, it is important to mix in the appropriate manure. This process is called taqlîb in the Bughya and should be a deep and consistent mixing. Details are given on the timing, number of plowings and depth of furrows for various crops. There is also a short agricultural calendar.

 

The bulk of the information in the Bughya is on the major crops and flowering plants cultivated in medieval Yemen. The Rasulid agricultural treatises follow the medieval scientific tradition in classifying cultivated plants. This classification is not the same as modern scientific usage, which complicates translation of generic Arabic terms into English. Most of the commentary in the Bughya is relevant to Yemen, especially for the Tihâma and southern highlands where the Rasulid sultans wielded power. In his description of each crop al-Malik al-Afdal provides a variety of information on its cultivation in Yemen, as well as comments from earlier non-Yemeni sources. Horticultural advice is given on pruning and grafting, as well as a general discussion of the medicinal and useful properties of certain plants.

 

 Yemeni sorghum (Ahjur, highlands).

 

One chapter is devoted to cereal grains, defined generically as hubûb in Arabic (cf. Serjeant 1974a for English translation). This covers wheat (burr), tetraploid emmer wheat ('alas), barley (sha'îr), sorghum (dhura), rice (aruzz), eleusine (kinab), lucerne (qadb), teff (tahaf) and sesame (simsim). In medieval Arab agricultural typology lucerne and sesame were classified with the cereals rather than with a specific group of leguminous plants. As an example of the kind of information provided by al-Malik al-Afdal, the following is recorded for sesame (Serjeant 1974a:58-59).:

"It is sown during the middle ten days [lit., nights] of Tishrîn I [24 October-3 November] and flowers in forty-three days. It stands a hundred days and is plucked up by its roots, carried to hard ground, and made into sheaves [and stacked?] load by load, and [by] two and three loads, and set up unitl it dries through [the action of] the sun and wind and its seed-pods open. then it is turned to the left, and so on, so that the sesame [seed] it contains runs out. It is sown in Tihâmah and in those mountains near the heat, rough ground containing no sand being selected for it. In the mountains stony land with many pebbles is selected for it. In Tihâmah it does not need much watering -- on the contrary it is enough to water the land once only before sowing, but in the mountains it must be watered a number of times. The ground is prepared for it by vigorous ploughing; four and more times. It is sown in the mountains -- and if it be land watered by rain alone this will be mentioned, if God wills; and if it be irigated land it [is sown] in Tishrîn II [14 November --]. When its seed forms and becomes firm it is watered a second time and left till it ripens. Some is scatter-sown, and some sown in the furrowing of the ground behind the [plough-] oxen -- this the cultivator calls tanam, though some say talam [? vocalisation], both technical usage, not [classical] Arabic."

 

In the Bughya (f. 35v) the term qatânî (plural) refers primarily to various legumes and pulses. Sesame is considered one of the grains (hubûb, plural); the Arabic classification does not coincide precisely with modern classification of these plants. Al-Malik al-Afdal distinguished fifteen varieties of qatânî. These included, in the order discussed: chick peas (himmas), lentils ('adas), mung bean (mâsh), cowpea (lûbiyâ'), broad bean (bâqillâ'), endive (hindibâ'), hyacinth bean (hurtumân), fenugreek (hulba), water cress (hilf), mustard (khardal), safflower (qurtum), poppy (khashkhâsh), flax (mûma), and black cumin (al-habba al-sawdâ').

 

Various fruits and vegetables are classified as buqûl and khadrawât (literally, "greens"), although the term used for fruit in general is fawâkih (plural). According to the Bughya ( f. 42r), buqûl were planted between XII:2-I:29 and ripened from the end of Nîsân (IV) through the month of Ayyâr (V). Thirty varieties of buqûl were distinguished. These were, in the order discussed: yellow and green melons (bittîkh), cucumbers (qiththâ' and khiyâr), pumpkin (qar'), eggplant (bâdhinjân), carrot (jazar), turnip (lift), radish (fijl), garlic (thûm), onion (baqal), leek (kurrâth), ginger (zanjabîl), lettuce (khass), endive (hindibâ'), lupine (turmus), colocasia (qulqâs), Swiss chard (salq), spinach (isfânâkh), Balsam of Kataf (qataf), purselane (rijla), mint (na'na'), pennyroyal (fûdanj), common rue (shadhâb), parsley (maqdûnis), celery (karafs), okra (bâmîya), asparagus (hilyawn), cabbage (kurunb), and Indian hemp (shâhtarraj).

 

Al-Malik al-Afdal (Bughya , f. 64v-66v) defined several herbs, distinguished by him as spices rather than foods per se. These were dill (shibith), coriander (kuzbara), fennel (râzayânaj) and black cumin (al-kammûn al-Habashî). Fennel grows wild in Yemen. Black cumin is an important spice used in certain kinds of Yemeni breads.

 

A wide variety of tree crops, shrubs and fruits are classified in the Bughya ( f. 81r-129v) as al-ashjâr al-muthmira (literally "flowering trees"). These included some thirty-four kinds of crops: date palms (nakhl), grapes ('inab), fig (tîn), balas fig, pomegranate (rummân), quince (safarjal), apple (tuffâh), plum ('ijjâs), pear (kumathrâ), peach (khawkh), apricot (mishmish), mulberry (tût), olive (zaytûn), walnut (jawz), almond (lawz), pistachio (fustuq), coconut (nârajîl), betel nut (fûfal), doum palm (dawm), carob (qaranfîl), banana (mawz), sugar cane (qasab al-sukkar), citron (utrujj and hummâd), orange (nâranj), lemon (lîmûn), tamarind (humar), lebbek tree (labakh), christ's thorn (sidr), Indian labarnum (khiyâr shanbar), ban tree (bân), cotton (qutn), madder (fuwwa), turmeric (hurd).

 

The agricultural almanacs of the Rasulid period are arranged according to the solar calendar (Varisco, in press). This was the medieval Julian reckoning according to the Syriac month names, starting with Tishrîn al-Awwal (October). As a consequence all dates mentioned in the medieval Yemeni almanacs and texts need to be calibrated with the actual solar date in our current Gregorian reckoning. The Rasulid dates are about eight days early in relation to our present calendar. Information is provided in the almanacs for each day of the year. While some of this is generic almanac lore borrowed from earlier sources, there is much valuable information on the timing of weather and agricultural activities in Yemen.

 

The authors of the medieval Yemeni texts were familiar with a variety of previous medieval treatises and sources. The main agricultural texts consulted by al-Malik al-Afdal in the Bughya were widely distributed in the medieval Islamic world. One was the so-called "Book of Byzantine Agriculture" (Kitâb al-Filâha al-Rûmîya) of the 6th century A.D. Cassianus Bassus. A second is the so-called "Book of Nabataean Agriculture" (Kitâb al-Filâha al-Nabatîya) of Ibn Wahshîya, an Iraqi of the 10th century A.D. who copied both practical and magical information of agriculture from earlier Syriac sources. The third major text was the "Book of Agriculture" (Kitâb al-Filâha) of the 11th century A.D. Spanish author Ibn Bassâl (1955; Millás Vallicrosa 1948 for Spanish translation). It is necessary to separate the Yemeni from the non-Yemeni information, a task complicated at times by the way in which the Yemeni texts were written. However, it is also important to note that certain methods described in non-Yemeni texts may have been applied in Yemen or may have become part of the indigenous agricultural system. To the extent any of the non-Yemeni data is appropriate, it should be considered for development of IPM in Yemen.

 

In order to interpret the medieval Yemeni texts, it is necessary to consult a range of Arabic sources, especially lexicons. The most important lexicon by a Yemeni author was the massive Tâj al-'Arûs of the 18th century Muhammad ibn Muhammad al-Murtadâ al-Zabîdî (N.D.). This draws on a number of earlier lexicons, including that of an earlier resident of Zabîd, the 15th century Muhammad ibn Ya'qûb al-Fîrûzâbâdî, who compiled al-Qâmûs al-Muhît. Both of these authors are particularly useful for terminology relevant to Yemen. A very important source for understanding medieval agricultural and botanical terminology is the major thesaurus in Arabic, the Mukhassas of the 11th century 'Alî ibn Ismâ'îl ibn Sîda (1965). Ibn Sîda (1965:11:56-60) provides an extended discussion of Arabic terms used to described pests and diseases of crops and stored grain. For useful details on specific animal pests, the most important sources are the early zoological works of al-Damîrî (N.D.) and al-Jâhiz (1968). There are numerous herbals, including a widely circulated Yemeni herbal compiled by al-Malik al-Muzaffar Yûsuf ibn 'Umar (1982).

 

An example of the kind of detail provided in the lexical sources can be found for the discussion of a worm called surfa in the lexicon of al-Zabîdî (s-r-f). A summary translation of this is provided here.

"A certain small creeping thing, dust-coloured, that constructs a beautiful habitation in which it is: or a very small creeping thing, like the half of a lentil, that bores a tree, and then constructs therein a habitation of pieces of wood, which it conjoins by means of what resembles the web of a spider; or a very small dust-coloured creeping thing, that comes to a piece of wood and excavates it, and then brings a bit of wood and puts it therein, then another, then another, and then weaves what resembles the web of a spider: or, according to Abû Hanîfa, a certain small creeping thing, like the worm, inclining in some degree to blackness, found upon [plants called] hamâd, that constructs a four-sided, or square, habitation, of pieces of wood, joining the extremities of these together by means of a thing [or substance] resembling the web of a spider: or the worm [or caterpillar] that weaves [a web] upon certain trees, and eats their leaves, and destroys the rest thereof by that weaving; or a certain worm [or caterpillar] like the finger, hairy, speckled with black or white, that eats the leaves of trees so as to make them bare: or a certain worm [or caterpillar] that weaves upon itself, of the size of a finger in length, a thing like the qirtâs [a roll, or scroll, or paper], which it enters, so becoming unattainable: or a certain light, small creeeping thing, like a spider."

 

In addition to texts on agricultural practices and plants, there is also the folklore in proverbs and literature. While this information is usually not useful for descriptive purposes, it can be relevant for designing extensions and communication messages. There are several published collections of Yemeni proverbs (e.g., al-Akwa' 1984), including those of the legendary 'Alî ibn Zâyid (Agaryshev 1968; al-Baraddûnî 1985), a sort of Yemeni "Everyman". Yemeni farmers in the highlands are fond of quoting agricultural sayings of this legendary figure.

 

3.3 Traditional Practices

 

There is a danger in discussing traditional agriculture in Yemen, because it is often assumed that the whole range of traditional farming systems can meaningfully be lumped together in contrast to modern farming systems. The main problem is that a particular type of subsistence agriculture, usually in a simplistic rendering, is often used to define the range of traditional systems. The assumption is that Yemeni farmers expended a great amount of energy and labor with only minimal results, sometimes insufficient for household use. In fact, there have always been rich and poor farmers in Yemen, just as there have been both successful and unsuccessful practices. Surviving practices may in fact only be remnants and cannot be used to judge the overall utility of a traditional system.

 

This section can only briefly address the complexity of traditional farming systems in the country. There are basically two main strategies in the history of Yemen's agriculture:

• Dry Farming. This is based on the timing of rains, which supply the essential moisture for crop production. In parts of Yemen, especially in the Southern Highlands, rainfall was usually more than sufficient for rainfed production. In other parts of the country, rainfall was far more sporadic and limited. Yet even in seemingly impossible contexts, fields could be cultivated because of sophisticated runoff harvesting systems (Eger 1984). Depending on the amount and timing of rainfall throughout Yemen, dry farming practices were often quite different from one region to another.

Highland dry farming terraces.

Irrigation channel in field with small basins.

 

• Irrigation. The other major strategy was use of supplemental irrigation water, even though rains might also be of importance. In the past the main sources of perennial water were natural or excavated springs and shallow wells (Varisco 1982a). Along the major coastal and some inland wadis there was also sufficient annual (or once every few years) flooding to support agriculture, often on a fairly regular basis, such as in Wadi Zabîd and Wadi Lahj (Maktari 1970).

 

Most of the farming systems were based on small farmer holdings, where most of the production was for household use. However, in prime irrigated areas and some areas receiving abundant regular rainfall there was at times surplus production for local, national and international marketing in the past. During the medieval period Yemen supplied wheat and fruits to Mecca. Yemeni agricultural products were traded east and west through the medeival port of Aden. In some cases the limiting factor on production was not the environment (primarily lack of rain or pest infestation), but rather the difficulties of marketing and storage. It is not the case that Yemeni farmers could not produce a surplus. Rather, there were economic factors apart from agricultural production methods per se that limited production.

 

The traditional farmer was oriented toward survival and sustainabiliy was thus a primary concern. As is true in much of the developing world, traditional farmers were more concerned about minimizing risk than they were with increasing yields. On the surface traditional practices may seem inefficient by today's standards of maximal economic returns. It cannot be assumed that these practices were inefficient per se, nor that they are only relevant for marginal subsistence cultivation. For example, the ard or scratch plow used in Yemen is being replaced by tractors where possible in Yemen. Yet for much of the dry farming systems in Yemen the use of a traditional plow results in less erosion and does not expose soil moisture at lower levels, thus allowing plants to better endure drought conditions (cf. Rajaram et al. 1991:152). In the United States new machinery that scratches or chisels the soil is rapidly replacing the standard moldboard plow (Sidey 1992:54-55). An estimated 281 million acres of cropland in the United States is now under some kind of residue management, which is a return to the type of traditional systems such as are found in Yemen.

 

Since traditional agricultural practices were applied within a different strategy than is the case today, it is important to study their wider context. In the modern development context, where farmers need not be self-reliant in order to physically survive, some of these same practices may yield efficient results under a different farming strategy. This is especially the case for those practices which contribute to overall crop protection, as described below in section 4.3.2.

 

It is important to examine the purpose for the range of traditional practices in a given farming system. For example, it has often been assumed that farmers in dry farming systems orient their practices only to maximise the moisture in the rainfall. While for many farmers no rain meant no gain, there were other risks to deal with. Timing of cultivation may be oriented more toward avoidance of pest or disease problems at a certain stage in the crop cycle (see section 4.3.2.1). In contemporary farming, when farmers plant according to market considerations, they may actually increase pest problems if a crop is at a critical stage when there is a natural increase in certain harmful pests. This requires the application of pesticides, while in some cases a return to previous planting times could reduce the pest problem.

 

 

Traditional Yemeni farming depends on animal power.

 

 There have been several detailed ethnographic studies of traditional farming systems in Yemen, although much of the information has been limited to broad geographic (Kopp 1981) or socio-economic information (Tutwiler and Carapico 1981). For the highland spring-irrigation system of al-Ahjur, Varisco (1982a,b; 1983, 1985) has provided ecologic details. Ethnographic details on Yemeni farming can also be found in studies by Bedoucha (1986), Dostal (1985), Dresch (1989), Gingrich and Heiss (1986), Maktari (1980), Messick (1978), Mundy (1981), Serjeant (1964) Steffen et al. (1978) and Tutwiler and Carapico (1981). Description of traditional practices compiled in the development assessments of Yemen's major wadis is usually superficial and often inaccurate. Much of this was collected by technical experts with no previous experience in the country.

 

3.4 Summary

 

In development contexts throughout the world there has been a growing awareness of the importance of understanding traditional agricultural systems as a necessary part of development planning. The range of indigenous knowledge in Yemen is particularly well suited for this purpose because of the rich heritage of medieval agricultural texts and the continued practice of traditional methods in many regions of the country. A survey of "traditional" faming in Yemen has yet to be written, despite the abundance of information. The scientific documentation of this indigenous knowledge is important for sustainable crop production and effective plant protection in Yemen's future development.

 

There is a wide range of indigenous knowledge on Yemeni farming and the environment. Within the literary tradition there are scientific texts with practical information on past farming methods and strategies, as well as references to agriculture in proverbs and other literary forms. Only a small part of this knowledge has been documented and virtually no analysis has been made of its relevance to modern farming systems. There have been several ethnographic studies of farming systems in contemporary Yemen, but only a few of these have dealt with ecological or development issues. Much of the ethnographic data has not been available for development planners.

 

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4. Traditional Plant Protection Practices in Yemen

 

4.1 General

 

Farmers in Yemen have long faced a number of problems in producing their crops. The primary protection needs, apart from economic and political aspects, revolved around natural events, harm from animals and various diseases that might affect the crop. There was no single response to the problems that might arise, so farmers in various communities developed their own approaches based on previous experience in the local environmental context. While some protective measures were no doubt widespread, farmers in one area may have hit upon a unique measure that was unknown elsewhere. Thus, some protection practices may not have been widespread, even if they were effective.

 

In their discussion of crops and flowering plants, both Yemeni sultans al-Malik al-Ashraf and al-Malik al-Afdal provided information on how to protect some of these. While most of this information was practical and clearly based on methods observed at the time, some is derived from earlier texts and some is clearly fanciful and irrational. It is not possible to confirm the use of all the practices mentioned as having been applied in Yemen, especially those herbal remedies enumerated in chapter fifteen of the Bughya (f. 100r-104r) by al-Malik al-Afdal. This chapter was devoted to the repelling (daf') of insects from crops, preservation of fruits, grains and flour, and driving away (tard) of locusts, worms and caterpillars (dûd), wasps, etc. (zanâbîr), and ants (naml), as well as control of harmful weeds (hashîsh) in fields. Much of this appears to be derived from the Classical tradition, stemming back to such authorities as Dioscorides and Pliny, while part is based on Arab and non-Arab magical traditions. Relevant information from this chapter is discussed below in sections 4.3 and 4.4.

 

Al-Malik al-Afdal provided a range of advice for "preventive" production. One of the recommendations was to choose the best seed (badhr), which is the strongest and healthiest. This should be seed that has not been infested by insect pests (e.g., sûs), nor affected by disease or rot ('afan), nor reached by rain or water (BF-22v). One of the ways farmers control the spread of sorghum smut in Yemen today is to remove all infected heads before or during the harvest and save only clean seed. A number of practices were suggested in the Bughya to minimize pest problems, especially in cases where pests or diseases attacked crops. These are discussed below in section 4.3.

 

It is important to note that virtually no research has been directed at how Yemenis protect crops in traditional farming systems, despite the fact that a fair amount of anecdotal information circulates. Until extensive research has been conducted in a systematic manner, it would be wrong to either praise Yemeni farmers as geniuses in crop protection or condemn them as ignorant peasants. This chapter documents a range of practices, either recorded in medieval Yemeni texts or still used by farmers, that contribute in some way to overall crop protection. Determination of which practices are sound should be part of the development of IPM for the country.

 

4.2 Major Pests and Diseases in Traditional Agriculture

 

Accompanying this report is a computerized data base organized into two main files. One file is devoted to specific pests (animal or plant) and a second to specific diseases identified for Yemen's agricultural crops. These should be consulted for detailed and updated data. This section provides a general analysis of the data collected thus far. Protection methods are discussed according to a classification shown below in Figure 4-1. A brief, but not complete, introduction to some of the major pests and diseases is provided below.

 

4.2.1 Animal Pests

 

There is a wide range of potentially harmful animal pests in Yemen. Some of these have been a problem for farmers for centuries, while others have only recently become a problem or have been introduced from outside. Major pests include small mammals (such as foxes, porcupines, rabbits, rodents, baboons), birds and insects (such as locusts, date palm scale, various moths and worms, aphids).

 

 

Aphids

 

Aphids (Aphis maidis) are a problem throughout Yemen. The usual term in Arabic for these is 'usâl or man. The cotton aphid (Aphis gossypii Glover) is called hilla or mu'asila near al-Kawd. One of the problems is that the eggs are placed on the underside of plant leaves, which the emerging larvae then consume. In Wadi Jîzân aphids can damage sorghum and prevent a second growth (Serjeant 1979:A2-4). Rain generally eliminates these pests. The larvae are attacked by ants and spiders. The cotton aphid is controlled by planting spate-irrigated sorghum in August and September (al-Kawd). A number of herbicidal plants are used against aphids worldwide (Grainge and Ahmed 1988:314-315), including Ricinus communis.

 

Baboons

 

The Arabian baboon (Papio hamadryas), locally known as rubâh (plural) in Arabic, is found in the Tihâma foothills, isolated parts of the western escarpment and Amîrî highlands of the south. It is considered an agricultural pest because it steals grain (Helfritz 1958:162; Kuczynski 1977:160; Scott 1942:48). In al-Ahjur of the central highlands farmers claim that baboons will raid a freshly sown field at night and dig out the seeds, raid grains just before harvest or steal grain from the threshing floor or granary. In the lower valley of Jabal Bura', where at present about 150-200 baboons live, they raid the newly planted banana plantations. In general the small number of remaining baboons does not appear to represent a problem except in isolated cases. In Hajja, for example, most of the baboons died of starvation or left the area during the civil war of the 1960s (Wilson 1978:210). By contrast, there are an estimated 200,000 baboons in Saudi Arabia, which has prompted Saudi scientists to embark on a program of vasectomies and hormone implant injections in an attempt to reduce the population (Noakes 1992:47).

 

Birds

 

Yemen has a diverse population of birds, many of which are also found in East Africa. In addition Yemen lies along the migration route during fall and spring. The generic term for birds in Yemeni Arabic is tayr, although 'asfar is commonly used for small birds. The term tayr is used in a number of dialects for any pest that flies, including locusts. Among the most common birds which are agricultural pests are pigeons (hamâm), swallows (khuttâf) turtledoves (jawlab). These eat ripening grain and fruit, such as grapes. Some birds also reduce the bee population (Jaycox and Karpowicz 1990:6).

 

Farmers throughout Yemen have always had to battle birds for their newly planted seeds and ripening crops. It is common to see scarecrows and items of clothing in fields to scare away birds. In some areas members of a household may sit in or near a field to physically frighten off birds. The 19th century traveler, G. Wyman Bury (1915:70, 98), remarked that in the irrigated gardens near Sanaa, the ripening crops are "guarded by high-perched slingers, whose strident curses and whirring clay projectiles hold the birds in check throughout the live-long day." Given the shortage of agricultural labor in many parts of the country today, it is no longer possible to have such labor-intensive guarding of individual fields.

 

Flies

 

There are a number of small flies which are pests of plants and crop produce. There is no generic term for these in Yemen. In the highlands the term nissa is used for small flies, fruit flies, mosquitos and gnats. In the Sanaa area when there is no rain a small nissa deposits a white sticky substance on grape and sorghum leaves, but this is washed off in the rain.

 

Fox

 

The fox is called tha'l in Yemeni Arabic; this is a variant of the classical tha'lab. Although the fox is more often considered a pest because of its attacks on chickens and domestic fowl, it also eats some produce. Near Sa'da the fox is known to eat grapes (Kuczynski 1977:160). The fox is generally controlled by hunting or more recently by setting out poison bait.

 

Locusts

 

The major insect pest in medieval Yemen was the jarâd or desert locust (Schistocerca gregaria), which would regularly swarm and periodically destroy many crops. In classical Arabic the term dabba is used for the locust when it first emerges from the egg. After this it is called ghawgha' at the time when it has developed wings. The term jarâd is applied to the male after he turns yellow and to the female after she blackens and can sing (al-Damîrî N.D.:1:187). The term for locust eggs is makn, although Niebuhr (1792:2:334) reported that in Yemen it could refer to a succulent and fat red locust. The hopper is often called dabâ in Yemen (e.g., Maktari 1971:162).

 

 

The Tihâma coast and eastern parts of Yemen provide suitable habitats for the locust (al-Humiari 1982:91). The historical texts frequently mention years in which there was major locust damage in Yemen. There may be as many as several hundred million locusts in a major swarm. Considering that the locust can live up to six months and that the female may produce 300-400 eggs in various places, it is not hard to imagine the damage that such a sizeable group can inflict on a farmer's fields. Locust swarms often came from Ethiopia and entered the southern part of Yemen in the winter (October-January) and then spread out to the north and northeast ; they would breed in the early spring rains and then return back through Yemen on their way to East Africa (Baron 1972:99).

 

The worst damage came from the hoppers, which could literally denude the land of edible foliage, rather than the flyers. Niebuhr (1792:2:335) noted that dates and vegetables were particularly susceptible to locust damage, but sorghum was generally spared because the seeds were hard. The early Islamic authority Abû Ziyâd (in Abû Hanîfa 1974:65) said that locusts would not damage the crop if it was first sprouting up, because of the potential for regrowth. Young hoppers are a pest of honey (Abû Hanîfa 1974:290). The medieval author Ibn al-Mujâwir (1954:227) described a variety of locust called Najdî (apparently from the region of al-Najd in Saudi Arabia) which did not eat foliage.

 

Recent locust eradication programs in the region have greatly reduced the threat of swarms, although disposal of outdated pesticides for locust control is a major environmental problem facing Yemen. There were several traditional ways of attempting to deal with locusts (see Annex A: Pests under "locust"), although these were usually no match for swarms. One ancient way of dealing with a locust swarm was to beat them with branches and drive them toward prepared trenches. Yemeni farmers also report using smoke to cover the crop, a method widely reported around the world. The medieval herbals record a number of botanical simples for helping ward off locusts, as noted below in section 4.3.1.2.

 

Perhaps the most beneficial was simply to eat them. It is reported that the Prophet Muhammad ate locusts (al-Dhahabî 1984:96). They are grilled and eaten in many parts of Yemen (e.g., at Sa'da in Kuczynski 1977:160; Hadramawt in von Wrede 1873:202). Niebuhr (1792:2:335) reported that Yemenis believed locusts thickened the blood and made one melancholy. The early Muslim savant al-Jâhiz (1964:4:43) thought there was nothing more tasty than grilled locusts.

 

Mice

 

The generic term for the mouse in Arabic is fa'r. The rat is usually distinguished as juradh. The mouse is a domestic pest which attacks stored grain in fields, threshing floors or houses. Some Yemeni houses have devised various types of mousetraps, but the most common remedy is to have several cats around.

 

Porcupines

 

The porcupine (Hystrix indica ?) is called by several names in Yemeni Arabic, including qumayra, 'anasa, shibrîza and am-shibrîta. The porcupines come out at night and eat sorghum and beans. In the Hajja area it is necessary to guard sorghum fields against porcupines, because the panther (nimr), its natural predator is virtually extinct (Wilson 1978:209). Farmers say this was not neccessary before the 1970s. Porcupines are also reported to attack qât trees in Wadi Dhahr (Serjeant 1974b:180).

 

Termites

 

The termite or white ant (Microcerotermes diversus Silvestri) is called arada in Yemeni Arabic. According to the lexicon of al-Zabîdî, there were two main types of arada: one looked like an ant and attacked wood, the other was like an ant with wings. The termite is found in virtually all parts of Yemen, but is a particular problem in the Tihâma and coastal zones. At the village of al-Mudamin near Zabîd the termite problem is so bad that doors to huts cannot be made out of wood. In addition to its destruction of all types of wood, and thus trees such as palms and fruit trees, it can be a problem on sorghum, maize, cotton, okra and tobacco. According to al-Zabîdî, the termite does not attack what is moist or succulent.

A number of methods were employed to repel termites, as discussed below in section 4.3.1.1.2, and 4.3.1.2. One of the most common plants used in Yemen to repel termites is Ricinus communis. Grainge and Ahmed (1988:361) list 39 plants which are said to be useful worldwide in control of termites. According to al-Damîrî (N.D.:1:19), the ant is a natural enemy of the termite and can be introduced to attack a termite mound.

 

 

Termites near Zabîd

 

Worms

 

The generic terms in Yemeni Arabic for worms and caterpillars or small bugs that are worm-like in appearance are dûd and sûs. The term sûs is often used for worms or small bugs smaller than those categorized as dûd. This broad use of the term covers a large variety of species of insects. One of the most problematic is the so-called African armyworm (Spodoptera exempta). This is called jarâmî in al-Ahjur of the central highlands. It attacks grain crops and vegetables, especially in June and July. According to Grainge and Ahmed (1988:359), there are 14 plant species which can help control the armyworm. The American bollworm (Heliothis armigera) is a problem on cotton and tomatos in the Tihâma and southern coastal zone. The stalk-border (Busseloa fusca) is a problem on sorghum, millet and maize. In al-Ahjur it is called dûda sawda. It is estimated to cause 25-30% crop damage on sorghum and maize in the coastal Wadi Surdud area. A variety is also reported to eat qât leaves in al-Ahjur. Other species recorded for Yemen are mentioned in al-Humiari (1982) and the data base.

 

 

Bollworm in cotton.

 

4.2.2 Plant Pests

 

A wide range of weeds and parasitic plants has been documented for Yemen (see Chaudhary and Revri 1983).

 

Bermuda grass

 

One of the primary weeds on cultivated fields in Yemen is Bermuda grass (Cynodon dactylon), which is generally called wabal or zîl in Yemen. This is a very difficult plant to eradicate from a field. It is found in virtually every region and was even mentioned as a problem in the medieval agricultural texts. Al-Malik al-Ashraf (MM-78-79) observed: "This is a persistent weed which grows freely and whose roots cannot be removed. This is the worst pest on crops, especially madder (fuwwa). One should not sow madder until all the soil which has this wabal has been removed so that its roots will be cut off. Then the ground must be well plowed and all remaining parts of the plant must be removed by hand." Most farmers know of no other solution that physically removing this weed from the field. In other countries the plant Plantanus occidentalis (eastern sycamore) has been shown to be effective in control of Bermuda grass (Grainge and Ahmed 1988:376-379). Although it is primarily a weed, this plant has a number of medicinal uses in Arab tradition, such as a diuretic (al-Khalîfa and Sharkas 1984:45, Maimonides 1979:171). Al-Malik al-Afdal (BF-108r) said this plant was useful as fodder for horses and mounts. It is commonly collected as fodder in Yemen today.

 

Orobanche

 

The orobanche (Orobanche cernua) is mainly problematic on solanaceous plants and for coffee. This is particularly a problem for tomatoes and invariably reduces the yield. It is apparently a problem with qât trees as well (Blatter 1921:3:352); Varisco observed it growing in qât and coffee fields in al-Ahjur in 1979. It was also observed that the local black ants were especially fond of the flowers of this plant, but it is unclear if ants could be used to control its spread. The orobanche has been controlled in southeastern Europe and the former Soviet Union with the native stem mining fly (Greathead and Waage 1983:29).

 

Orobanche in Ahjur, Highlands.

 

 

Witchweed

 

Witchweed (Striga hermonthica), a parasitic plant with purple flowers, is called 'uddâr in the central highlands and Tihâma. It is primarily a problem on sorghum. Several local varieties of sorghum, are resistant in Yemen (Univ. of Arizona 1981:vi, 22). Crop rotation, use of trap crops and effective tillage can limit witchweed attack (Greathead and Waage 1983:23).

 

 

4.2.3 Diseases

 

A wide range of information is available on diseases of Yemeni crops due to previous research in the YGPPP and its predecesors. However, most of this is for introduced crops. The medieval agricultural texts describe a variety of diseases for particular crops, especially for date palms and grapes. The specific diseases of date palms are discussed in section 4.5 below.

 

Sorghum smut (Sphacelotheca spp.) is found throughout the country, although it is not a serious problem on most traditional varieties. The local names for this smut are ja'dab, khurmuj, tafahham, 'ukâb and khurma'. This is a disease in which the heads of sorghum are blackened and dry up before fully maturing. There are a number of traditional methods for handling this problem. In Silw farmers mix seed with lime (nûra) and water before planting. In Wadi al-Barakânî dry lime is applied to the seed before planting. Many farmers interviewed control by selecting the best seeds for sowing and burning the affected heads.

 

4.3 Range of Plant Protection Measures

 

This chapter summarizes the kinds of practices among Yemeni farmers which contribute in plant protection either directly or indirectly. Many of the traditional crop protection methods documented for other countries (e.g., Grainge and Ahmed 1988; Thurston 1992) can also be found in Yemen. Examples of indigenous methods in Yemen are presented below according to criteria presented in Figure 4-1. Some of these methods are known to have been applied by Yemeni farmers, while other practices may have been known only to a small circle of scholars or only a theoretical basis. It should be stressed that listing of information here does not indicate endorsement or verification of claims. The purpose is to identify the range of potentially practical information and encourage scientific study in Yemen.

---

Figure 4-1. Elements of Traditional Crop Protection

 

1. Direct Intervention

-- Biological control (e.g., predator, trap plant)

-- Soil/natural substance application

-- Water application (rain, irrigation, etc.)

-- Smoke/heat application

-- Manual removal

-- Protective device (basket, fence, stake, etc.)

 

2. Planting Technique

-- Timing

-- Location (microclimate, depth of planting, type of soil, etc.)

-- Crop density

-- Care of plant (thinning, shading, etc.)

-- Tillage technique

-- Transplanting/grafting

-- Crop sequence, rotation, use of fallow

-- Interplanting

 

3. Crop type

---

 4.3.1 Direct Intervention

 

One of the most obvious ways to deal with a plant pest or disease is to directly intervene to prevent or remove the problem. In modern agricultural systems this has become the main form of protection through reliance on application of pesticides, herbicides and fungicides. In traditional systems there was a limited number of proven methods of direct intervention, many of which were only partially effective or contingent on a combination of practices. The most common method was biological or botanical control, as is true in most traditional farming systems. Many protection measures were aimed at reducing the problem rather than eradication of the specific pest or disease.

 

4.3.1.1 Biological Control

 

Before the development of chemical pesticides, farmers were reliant on using nature itself to assist in crop protection. Through local experience farmers learned which animals were natural or induced predators of crop pests and which plants contained certain properties harmful or repellant to crop pests. There is a wide literature on traditional methods of biological control (e.g., Baker and Cook 1974; Cook and Baker 1983; Heitefuss 1989:217ff; Papavizas 1981;Thurston 1992:29-35), including application to modern farming systems.

 

The classical method of biological control is to introduce an organism or plant in order to resolve a pest problem, most commonly by finding a natural predator of the specific pest. It is also possible to use parasites (which weaken but do not necessarily eradicate pests), parasitoids (which develop in a single pest organism and eventually kill it), pathogens (parasitic microorganisms which kill the host), or antagonistic species which indirectly reduce the pest population through competition. Another form of biological control is to conserve the existing population of predators rather than directly introduce species for targeted pests.

 

The medieval agricultural texts, including the Rasulid treatises from Yemen, mention a number of remedies for crop problems through the medium of plant, animal or other natural substances. Yemeni farmers interviewed during this project also identified several animals and plants used in traditional biological control. These are discussed below for both animal and plant examples.

 

4.3.1.1.1 Animal

 

In nature there is a continual struggle for existence that may go unnoticed by farmers. The development of agricultural fields, choice of crops and methods of cultivation have an impact on the natural balance of predators and prey. In some cases a potential insect pest may be held in check with no need for action by the farmer. Yet, there are numerous cases where pests, particularly insects, pose a direct threat to the farmer's crops. In the event of a major infestation, such as seasonal locust swarms, there may be little that the farmer can do to protect his standing crop. Yet with pests which attack a certain stage of growth or only appear at a certain season, it may be possible for the farmer to use the natural predator-prey relationship to his advantage.

 

The introduction of predator species has a long history and has been instrumental in stemming major crop problems of the past. By the year 1978 over 750 insect species had been documented worldwide as successful predators for control of some 250 species of invertebrate agricultural pests (Greathead and Waage 1983:5). For example, when the cotton cushiony scale threatened to destroy citrus production in California during the last century, the Vedalia lady beetle was introduced and effectively controlled the problem. A wide variety of insects and other animals are used worldwide for plant protection. One of the most effective has been the lady beetle or ladybug (Rodalia cardinali or Hippodamia convergens). These ladybugs consume large quantities of aphids, scale insects, mites and mealy bugs (Seymour 1990:680). These ladybugs are not native species in Yemen.

 

One of the main forms of biological control in traditional Yemeni agriculture is use of certain ant species to eat the larvae of the date palm moth. In the 18th century, the traveller Osgood (1854:86) remarked on date palm production in Yemen that "when the fruit is first forming, large numbers of ants are collected and placed on trees, whereby destroying small destructive insects they do a much more valuable service than is compensated by their own slight injury to the fruit." This is a practice also described in the 13th century treatise of al-Malik al-Ashraf (MM) as follows: "This caterpillar (dûd) attacks the maturing date balah. You take a small black ant (qa's), which is in the tamarisk (ithl) tree. Take it to the bottom and head of the tree. Put a piece of wood with these ants near the balah date, and these ants will eat the caterpillar but not the balah date."

 

This method is still practiced in the Tihâma coast and in the Hujarîya region. The ant is called qa's in the Tihâma, 'is'is in the western part of Hujarîya or 'isfit in the eastern part of Hujarîya. Both black or red varieties are used. The black ant is said to be stronger and more successful than the red. If the two types of ants are too close together, it is said that the black ants will eat the red ants, so they must be kept apart. The black ant lives in the following trees: qarad (Acacia nilotica), 'ilb (Ziziphus spina-christi) sumar (Acacia tortillis), 'athl (Tamarix nilotica), mostly in temperate areas. It is not the species native to the Tihâma. According to farmers near Zabîd, they bring a piece of wood containing the ants from the mountains. This wood is placed in the palm near the date flower. Or ants are placed near the bottom of the tree to eat different pests which rise from the ground. The ants eat the pests, but not the dates. In Hujarîya this only needs to be done one time and the ants will continually stay for the life of the tree. In the Tihâma near Zabîd, however, this treatment must be done every year, according to local farmers.

 

Black ants used to contgrol date palm moth larvae.

 

In the medieval Arabic scientific tradition, ants were also said to be natural predators against termites and could be used to control them (al-Damîrî N.D.:1:19). There is a vast terminology for ants in Arabic, much of this discussed in the medieval thesaurus of Ibn Sîda (1965:8:119-120).

 

Predatory red ants (Formica rufa ) have been used to reduce population outbreaks of Lepidoptera and saw flies in European woodlands (Heitefuss 1989:219). The Tanzania "maji-moto" red ant is encouraged to nest near coconut trees in order to control the coreid bug, Pseudotherapthus wayi (J. ter Vrugt, personal communication). Dodge and Rickett (1948:59), however, warn that sometimes ants can spread the pest, as in the case of aphids in the United States.

 

The medieval texts, following Classical tradition, cited several uses for animal products in pest control. The rationale is that the scent of the animal or its product would repel certain pests. Al-Malik al-Afdal (in Serjeant 1974a:40) claimed "If wheat or other seed be placed in earthenware pots and covered with a hyena-skin in such a way that the smell of that skin can pervade it then it will stay free of all pests." He also claimed (BF-101v) that the skin of hyena in a field would keep birds away. The ancients placed great stock in hyena skin, with Pliny recognizing some 79 remedies involving it. The Bedouin of the Egyptian Sinai prize hyena fat as an ointment (Ruffer 1919:23). Al-Malik al-Afdal (BF-101r) also claimed that the skin of an adult porcupine, if put through a sieve and applied to a field, would ward off insect pests.

 

4.3.1.1.2 Botanical

 

One of the most common ways of traditional pest control is botanical control, either as a trap plant or the use of a specific plant part or derivative of that plant to repel or kill pests and improve disease conditions. A wide variety of plants have toxic properties which can be effective in pest and disease control. For example, some 240 plant species are said to be beneficial in control of the black carpet beetle or Attagenus piceus (Grainge and Ahmed 1988:viii). Some of the most common modern botanical pesticides come from plant toxins (Seymour 1990:521). For example, Rotenone is derived from Derris elliptica, Cubé barbasco, or Tephrasia virginiana . This is a potent stomach and contact poison for most insects and fish. Pyrethrum comes from the dried flowers of Chrysanthemum cineraiifolium; this is a short-lived poison for insects.

 

Plants used in pest or disease control in Yemen: These include plants currently used by Yemeni farmers or recorded in agricultural and medicinal texts available in medieval Yemen. Some of the plants are well-known and widely used in other countries, while others require further scientific analysis in order to isolate the relevant toxins in the plant or beneficial aspect of the plant.

• Albizzia lebbek L. (labakh) or lebbek tree. The smoke of this is said to drive off insect pests (al-Antâkî 1952:I:278). This is planted in Yemen and was described in the medieval Yemeni agricultural texts. The non-Yemeni species Albizzia odoratissima is said to have pest control properties for termites (Grainge and Ahmed 1988:361).

• Allium cepa L. (basal), the onion, is known throughout Yemen for its protection properties. In Banû Hushaysh onion is planted next to grapevine seedlings in order to ward off a small white worm called sulaylî. Ibn Wahshiya (in SA-133) said that an application of onion leaves mixed with turnip leaves and cow dung was useful in order to keep the sesame from blackening and spoiling. Onion is a well-known toxin to pests in the scientific literature (Grainge and Ahmed 1988:16-17). It can also be used to repel moles and aphids (Ware 1988:5). Onion has a wide variety of medicinal uses in the Middle East, especially against certain kinds of bacteria (Honda et al. 1990:112; al-Khalîfa and Sharkas 1984:55).

• Allium sativum L. (thûm) or garlic. The Arab texts, following Democritus, recorded that a wheat crop smoked with garlic (thûm) will cause pests (i.e., dûd) to drop off (SA-126). Garlic is a well-known toxin to pests in the literature (Grainge and Ahmed 1988:17-18). Garlic or chives interplanted with lettuce or peas will reduce the extent of aphids (Ware 1988:4). Garlic interplanted with tomatos will repel asparagus beetles (Seymour 1990:121). An extract of allyl sulfide from garlic is effective against mosquitos. There are a number of recipes for a garlic wash for plants. One of these is: soaking 3 ounces minced cloves of garlic in fish emulsion or mineral oil for 48 hours; then add about a pint of warm soapy (not detergent) water; store this in glass or china; dilute 1 part this mixture to 20 parts water for a spray (Seymour 1990:521).

• Brassica nigra L. (khardal) or black mustard. White mustard is Sinapis aliba L. If this is sown at borders of fields, it is claimed to ward off locust hoppers (Ibn Qutayba 1949:75). Mustard has a variety of medicinal uses in Yemen (Honda et al. 1990:107).

• Calotropis procera ('ushâr) of the Asclepiadaceae is a widely distributed shrub found up to 2000 meters elevation. In the Hadramawt the stalks of this plant are cut in small pieces and placed in irrigation channels. The sap which mixes with the irrigation water is said to ward off pests from the crop, especially an insect called sirw on sorghum and another insect called dhuwayna. Grainge and Ahmed (1988:58) record its use against swallowwort and locusts. The non-Yemeni species Calotropis gigantea is said to have pest-control properties against termites (Grainge and Ahmed 1988:361). The leaves contain cardenolides useful as an antiseptic for skin infections and the sap serves as a local anaesthetic (Fleurentin and Pelt 1982:98-99). This tree has numerous medicinal uses in Arab tradition (al-Khalîfa and Sharkas 1984:260).

 

 

Calotropis procera (‘ushar)

 

• Citrullus colocynthis (hanzal) or colocynth. A concoction of this and lupine boiled in water and sprinkled on fields is said to ward off locdsts (Ibn Qutayba 1949:75). This is originally a Greek remedy also mentioned by al-Malik al-Afdal (BF-101v). Colocynth is widely recognized as a repellant for caterpillars and moths (Grainge and Ahmed 1988:81). It has a variety of medicinal uses, including as a strong laxative and against diabetes (Honda et al. 1990:107-108; al-Khalîfa and Sharkas 1984:334).

• Cordia myxa (sabastân) or Sebesten's plum. This is part of a herbal remedy against the date palm disease called al-sill wa-al-diqq (BF-83r).

• Cucumis sativus (khiyâr) or cucumber. This is part of a herbal remedy against the date palm disease called al-sill wa-al-diqq (BF-83r). It can be planted near a palm with the disease known as yaraqân (BF-83r,v).

• Cucurbita maxima (qar') or pumpkin gourd. This is part of a herbal remedy against the date palm disease called al-sill wa-al-diqq (BF-83r). It can be planted near a palm with the disease known as yaraqân (BF-83r,v).

• Cupressus sempervirens L. (sirw) or cypress. The Arab texts, following Democritus, claim that dried leaves of this plant plus Plantanus orientalis (dulb), if planted with wheat seed, would retard all manner of pests (SA-126). The same reference recorded that a wheat crop smoked with cypress (sirw) wood, will cause pests (i.e., dûd) to drop off.

• Hordeum vulgare (sha'îr) or barley. This can be planted near date palms in order to treat a disease called yaraqân (BF-83r,v)

• Lupinus termis (turmus) or lupine. A concoction of this and colocynth boiled in water and sprinkled on fields is said to ward off locusts (Ibn Qutayba 1949:75). This has a variety of medicinal uses, including against diabetes (Honda et al. 1990:111).

• Myrtus communis (âs) or myrtle. This is used in a herbal remedy for a disease of miscellaneous weakness affecting date palms (BF-83r).

• Nerium oleander L. (diflâ) or oleander. Al-Malik al-Mujâhid (BF-100r) said that the branches of this placed in the hole with a plant would help prevent harmful weeds. This plant is poisonous and can kill camels who pasture on it (Nicolaisen 1963:177). It is found in the Hadramawt, but appears to have been introduced.

• Plantago psyllium (bazr qatûnâ) or flea-wort. This is part of a herbal remedy against the date palm disease called al-sill wa-al-diqq (BF-83r).

• Portulaca oleracea var. sativa ( al-baqla al-hamqâ' or rijla) or purselane. The sap of this plant is rubbed onto the date palm in oder to counteract a disease called jarab (BF-82v).

• Ricinus communis L. (kharwa' or tubsha'or shajarat al-zayt), the castor-bean or castor oil plant, of the Euphorbiaceae is a common tropical plant found up to elevations as high as 3000 meters. It grows up to four meters high. This is a very suitable shade tree, due to the large size of the leaves. It is not used as pasture in Arabia. In the Tihâma and Silw of the southern highlands this tree is said to help retard termites if planted along the edges of fields with tree crops such as qât, coffee, guava and mango. It is also planted near houses to keep termites away. In the Hadramawt the branches are cut and spread in cotton fields to keep insect pests away. The leaves of the castor bean plant are recognized as a natural repellant for insects, if the fruit or crop is washed with a concotion of these (al-Khalîfa and Sharkas 1984:177). Some of the active components in the oil are Ricinoleic acid, Ricin and D-galactosyl. Ricin, which is found on the coats of the seeds, is a well-known toxin for many insect pests and vermin (Everett 1982:2939). One of the applications of this tree is to help control locusts (Grainge and Ahmed 1988:58). The seeds produce an oil used as a laxative in Yemen (Fleurentin and Pelt 1982:94-95) and elsewhere (Honda et al. 1990:107). The medicinal uses as a cathartic, emetic and skin cleaner were recognized by the Greek Dioscorides as early as the first century A.D.(Riddle 1985:124). It is a well-known modern therapeutic with application in chemotherapy and spermicides.

• Thymus glaber (nammâm) or wild thyme. This is used in a herbal remedy for a disease of miscellaneous weakness affecting date palms (BF-83r).

• Veratrum album L. (kharbaq). This is false hellebore used as a poison to kill mice, according to various Arab herbals and Dioscorides (Levey 1973:60; Riddle 1985:118). This is not a native plant of Yemen, but was probably introduced in the medieval period. Al-Malik al-Afdal (BF-100v) said this was useful as a repellant if crushed and sprayed with water on the furrow with seed, and if mixed with seed could also kill birds. He also claimed (BF-102r) that a mixture of hellebore and myrrh would keep ants away from wheat. This is a well-known toxin to many pests and vermin (Grainge and Ahmed 1988:1). One recipe is to mix 1 ounce hellebore to 2 gallons water with a little lime or flour added (Seymour 1990:521).

 

Plant species present in Yemen that have been said to be beneficial in pest control elsewhere: These are listed separately, because it is uncertain if Yemeni farmers have made use of them in the past. However, this represents a sample of potential indigenous or already introduced plants that might be used for pest control in the future.

• Acacia nilotica L. (sant, samur, talh). This is the classic gum-Arabic tree, of which two subspecies are present in Yemen: indica and kraussiana (Dubaie and Al-Khulaidi 1990:56-57). In Sudan a part of this tree i