Assessing the feasibility of biological control of locusts and grasshoppers in West Africa: Incorporating the farmers' perspective

Agriculture and Human Values 18: 413–428, 2001.© 2001 Kluwer Academic Publishers. Printed in the Netherlands.

IN THE FIELD

Assessing the feasibility of biological control of locusts and grasshoppers inWest Africa: Incorporating the farmers’ perspective

Hugo De Groote,1,2 Orou-Kobi Douro-Kpindou,2 Zakaria Ouambama,3 Comlan Gbongboui,2

Dieter Müller,2 Serge Attignon,2 and Chris Lomer2

1CIMMYT, Nairobi, Kenya; 2Institute of Tropical Agriculture (IITA), Locust and Grasshopper Biological Control Project(LUBILOSA); 3Comite Permanent Interetats de Lutte contre la Secheresse au Sahel (CILSS-AGRHYMET), Niamey

Accepted in revised form January 30, 2001

Abstract. A participatory rural appraisal in three West African countries examined the possibility for replacingchemical pesticides to control locusts and grasshoppers with a biological control method based on an indigenousfungal pathogen. The fungus is currently being tested at different sites in the Sahel and in the humid tropics ofWest Africa. Structured group interviews, individual discussions, and field visits, were used to obtain farmers’perceptions of locust and grasshoppers as crop pests, their quantitative estimation of crop losses, and their will-ingness to pay for locust control. Farmers as well as plant protection officers generally perceived locusts andgrasshoppers as important pests that cause significant damage. Farmers were aware of some of the risks of theuse of chemical pesticides, but not of the potential alternatives. The use of the fungus in an oil-formulation andstandard Ultra Low Volume (ULV) equipment was demonstrated, and the results discussed with farmers. Theirimpressions of biological control were favorable, and they expressed an interest in using the technology. Farmers’expressed willingness to pay for locust control is small, but not negligible. Locusts and grasshoppers are veryvisible pests and thus amenable to pressure from farmers to local administrators, as well as by farmers’ relativesin the city on the national government. Therefore, political pressure for locust control is strong, although nationalgovernments spend little on it, depending mostly on foreign donors. Donors are increasingly worried about theenvironmental effect of the large amounts of chemical pesticides used on locust control, and are pushing formore benign alternatives. The results of the present survey indicate that there may be a potential market for abiopesticide against grasshoppers and locusts on cash crops in the humid areas. The potential market in the Saheldepends on a reduction of costs or a subsidy of its price. This subsidy could be justified by the expected reductionin environmental and health costs when replacing chemical pesticides. Since donors are the current purchasers ofchemical pesticides for the Sahel, they would also be expected to be involved in the purchase of the biologicalproduct.

Key words: Biological control, Grasshoppers, Locusts, Participatory rural appraisal, West Africa, Willingness topay

Hugo De Groote is from Belgium and is an agricultural economist, with focus on participatory researchand pest control, and was previously coordinator of IITA’s biological control and biodiversity project. He iscurrently with CIMMYT’s Insect Resistant Maize project in Nairobi, Kenya.

Orou-Kobi Douro-Kpindou is a Benin agronomist-entomologist with IITA, Cotonou, in charge of fieldoperations in Mali of the collaborative project on biological control of locusts and grasshoppers (LUBILOSA).

Zakaria Ouambama is an agronomist-entomologist with CILSS-AGRHYMET in Niamey, in charge ofLUBILOSA’s field operations in Niger.

Comlan Gbongboui is a lawyer with IITA, Cotonou, in charge of LUBILOSA’s field operations in Beninof the collaborative project on biological control of locusts and grasshoppers (LUBILOSA).

Dieter Müller is a Swiss trainee agricultural economist, working on LUBILOSA’s participatory learning andaction program in Benin. He left for Brazil to start a dairy farm.

414 HUGO DE GROOTE ET AL.

Serge Attignon is a Benin agronomist with IITA, Cotonou, and a research assistant for economic analysis andGeographic Information Systems.

Chris Lomer is from the UK and is an entomologist and LUBILOSA project leader.

Introduction

The desert locust plague of 1986–1989 in North andWest Africa was the first in over 30 years, and causedconsiderable concern amongst farmers, the public, anddecision makers. The upsurge found the authoritiesand the regional locust control organizations unpre-pared: funds had been cut for many years, trainedteams were dispersed, and the most effective pesti-cide, dieldrin, was no longer being used because ofits toxicity and persistence. The substitute organophos-phate pesticides, such as fenitrothion and malathion,had shorter environmental persistence and were oftenrepeatedly applied as blanket treatments over largeareas. Ironically, such treatments may have causedgreater environmental damage than dieldrin (Rowleyand Bennett, 1993).

To counter the locust threat, $275 million wasraised and a total area of 25.9 million ha wastreated (OTA, 1990). Most multi-lateral assistancewas channeled through the FAO, which workedwith national and regional organizations and privatecontractors to carry out the control operations. Atthe same time, dissatisfaction with the heavy andcontinuing use of chemical pesticides was growing(Louis Berger and Associates, 1991), and severalprojects were initiated to investigate the environmentalimpact of the treatments and to research alterna-tive control methods (Lomer and Prior, 1992). TheLUBILOSA (Lutte Biologique contre les Locustes etles Sautériaux) project was designed as a consortiumto develop a biological pesticide based on oil formu-lations of indigenous, specific fungal pathogens oflocusts (Prior and Greathead, 1989).

In the initial phase of the project a biopesticide wasdeveloped based on the spores of a fungus, Metar-hizium anisopliae var. acridum, a natural pathogen oflocusts that is virulent but highly specific (Lomer et al.,1997). A pilot plant was developed for the productionof large quantities of spores, and an oil-based applica-tion formulation was developed (Bateman, 1997b). Inthe second phase of the project (1993–1995) field trialswere carried out on different locusts species in severalAfrican countries (Lomer et al., 1997), including thoseof the humid tropics of South Bénin (Douro-Kpindouet al., 1995) as well as the Sahelian species in Niger(Langewald et al., 1999) and Mali (Shah et al., 1998).

The results are promising, with mortality rates of80% or higher being reached after one or two weeks.Moreover, the product is easy to produce (Jenkins etal., 1998; Cherry et al., 1999), and it can be stored asdry spores, which are easily applied in an oil formu-lation with standard spraying equipment (Bateman,1997a).

An ecotoxicological study in the millet produc-tion system in Niger (Peveling et al., 1999) showedthat the Metarhizium biopesticide poses low risk toall taxa monitored, which included 16 species fromthree different insect orders, as well as to other arth-ropods. In Mauritania, Peveling and Damba (1997)showed that fungal control of locusts in dates is anenvironmentally safe and economically viable alterna-tive to chemical control. The developed biopesticide,however, does not provide a direct substitute for chem-ical pesticides in emergency situations, but representsa powerful technology for integrated pest management(Lomer et al., 1999, 2001). Preliminary assessmentsof its economic viability were difficult as the imple-mentation pathway, production costs, and operatingcharacteristics had to be tested and defined (Swanson,1997; Stonehouse et al., 1997).

To bring the technology to the end user, stake-holders’ interest in this new technology needs to beassessed. More specifically, the interest of the farmers,policy makers, plant protection agencies, and donorsneeds to be assessed, the benefits of the technologyneed to be compared to the costs, and potential soci-ological constraints examined. Earlier studies showedthat farmers in different Sahelian countries gener-ally consider locusts and grasshoppers as major pests(Stonehouse et al., 1997). However, farmers find locustcontrol to be beyond the individual’s capacity, and soconsider it the government’s responsibility. Govern-ment intervention is only justified if the benefits tosociety would outweigh the costs, but unfortunately,few data are available to make such an analysis. InNiger, a three-year national crop loss survey on milletindicated that locusts and grasshoppers cause relativelysmall losses, questioning the economic justification oftheir control (Krall et al., 1995). Similarly, pooling thelimited available data on desert locust supplementedwith modeling concluded that the cost of desert locustcontrol is higher than the benefits in most foreseeablecircumstances (Joffe, 1995, 1997).

BIOLOGICAL CONTROL OF LOCUSTS AND GRASSHOPPERS IN WEST AFRICA 415

Table 1. Sites of the PRA and number of villagers participating.

Country District Village Date (1997) Longitude Latitude Paticipating

villagers

Men Women

Niger Maine-Soroa Gel Adoua August 29 12◦16′40′′ N 13◦22′00′′ E 21 0

Maine-Soroa Kayaya August 30 12◦40′15′′ N 13◦22′00′′ E 12 0

Maine-Soroa Bara August 31 12◦16′40′′ N 13◦10′59′′ E 9 0

Mali Goundaka Koa June 9 14◦29′31′′ N 4◦01′08′′ W 11 0

Kani Golokanda June 10 14◦19′31′′ N 3◦44′28′′ W 16 5

Dourou Yawa June 10 14◦17′59′′ N 3◦25′08′′ E 12 1

Dourou Nombori June 11 14◦19′47′′ N 3◦24′16′′ E 22 0

Benin Aplahoue Hontuoui March 12, 13 6◦54′50′′ N 1◦41′12′′ E 30 35

Djakotome Zouzouvou May 21 6◦54′05′′ N 1◦41′12′′ E 28 25

Eglime Eglime May 22 7◦5′17′′ N 1◦40′59′′ E 25 20

In the present debate, the farmers’ voice is seldomheard. Therefore, the present study was undertakento incorporate the perspectives of the farmers andother stakeholders in locust prone areas of Niger,Benin, and Mali, as part of the participatory researchby the LUBILOSA project. Elaborating on previouswork (Stonehouse et al., 1997) and extending it tothe humid zones, we studied farmers’ ranking ofcrop pests and their quantitative estimates of croplosses, their interest in and willingness to pay forlocust control, and their evaluation of the biopesti-cide in locust and grasshopper control. The opinionsof other stakeholders such as extension officers, plantprotection agencies, non governmental organizations(NGOs), and officials were also sought. To reflectthe large difference between sites, in the physical aswell as in the human environment, we chose the flex-ible approach of Participatory Rural Appraisals, andadjusted the intensity of the participatory approachaccording to the requirements of the situation.

Methodology

Background

Before starting the participatory component of theLUBILOSA project, the technical feasibility of thetechnology was tested in a number of field sitesin Niger, Mali, and Bénin (Douro-Kpindou et al.,1995, 1997; Kooyman et al., 1997; Lomer et al.,1993; Lomer, 1997). Sites selection was based on aconsistent presence of important grasshopper or locustspecies, good accessibility, and a good geographicdistribution. Since farmers in those sites had first-hand

experience with the new technology, the most prom-ising areas were retained for the participatory research,namely the Dogon country in Mali, the northern halfof the Mono province in Bénin, and the subdistrict ofMaïné-Soroa in Niger (Figure 1).

The control method used in all sites was based onthe same pathogenic fungus, Metarhizium, applied asan oil formulation of spores. The use strategy andapplication technology, however, differed consider-ably between sites, depending on the locust and pestcontrol strategies found in the different countries. InNiger, large fields were sprayed by airplane withoutany farmers’ participation, whereas in Mali, the testsites were treated with hand held sprayers by villagebrigades – farmer groups who have been trained andequipped for locust control. In South Bénin, neitherairplanes nor village brigades are commonly used, soan appropriate strategy still had to be designed anddifferent application technologies were tested.

Because of these differences, a flexible approachin the participatory rural appraisal was indicated,and although the appraisal covered the same topics(farming systems, pest problems, and evaluation of thetechnology) the level of detail needed differed consid-erably between sites. In Niger, where farmers’ activeparticipation was not required, group interviews takingabout two hours were sufficient. In Mali, the farmers’experiences with village organizations and chemicalcontrol needed more attention, and group interviewswere combined with other techniques, which tookabout half a day per village. In Bénin, where farmingsystems are more complex and a use strategy stillneeded to be developed, one or two days per villagewere necessary.

416 HUGO DE GROOTE ET AL.

Figure 1. Survey sites for the Participatory Rural Appraisal.

Concepts

Regardless of the intensity, the objectives of theparticipatory research remain the same: to improveefficiency of the research by paying more attention tothe preferences and the opinions of its final clients,the farmers (Chambers et al., 1989). Although theevidence of the expected efficiency increase fromparticipatory research is not well documented (seeBentley, 1994, for a critical overview), farmers’participation in agricultural technology development isincreasingly solicited. The different levels of intensityused in the appraisals can best be understood byplacing them in a conceptual framework based onthe four categories of participatory research by Biggs(1989), according to the level of farmers’ participation.

The most basic type of participatory researchis called contractual, where the trial is designedand managed by researchers, and the farmers onlyprovide land or services for the field trials. Theinitial trials of LUBILOSA in Niger, Mali, andBénin fall in this category. In a second type, calledconsultative, scientists consult farmers about theirproblems before developing solutions, often by usingRapid Rural Appraisals, a reaction against the tediousand costly traditional assessment surveys. In thismethod, multidisciplinary teams assess a rural area

within a short time using various techniques such asgroup discussions and interviews of resource persons.This method was used for this study in Niger, incombination with demonstration trials. The term is,however, no longer popular, since it emphasizes speedover participation, so we will refrain from using itfurther.

Lately, the emphasis has been on involving farmersin the earlier stages of technology development, soresearch can focus more on their problems and becomemore efficient (Kamara et al., 1996; Sperling et al.,1993). Biggs (1989) groups these approaches in athird category, the collaborative approach, in whichscientists and farmers collaborate as partners in theresearch process. Similarly, Rapid Rural Appraisalbecame Participatory Rural Appraisal, moving froman appraisal from the researcher’s point of view, to anappraisal conducted by the farmers. LUBILOSA’s laterefforts in Mali fall into this category, where the tech-nology is tested by farmers’ organizations, with thesupport of an NGO. Farmer’s opinions and suggestionsare actively sought and incorporated into the researchagenda.

In a fourth category of participatory research,collegial, scientists work to strengthen farmers’ ownresearch and development systems in rural areas. Inthis sense, Participatory Rural Appraisal moved from

BIOLOGICAL CONTROL OF LOCUSTS AND GRASSHOPPERS IN WEST AFRICA 417

appraisal to learning and action, implying a joint effort,now often called Participatory Learning and Action(since this term has not yet gained popularity we willagain refrain from using it further). This rather intenseapproach is only feasible where researchers are rela-tively close to the farmers, which for LUBILOSAmeans close to the International Institute of TropicalAgriculture station in Bénin. Here, farmers partici-pated in the design as well as in the evaluation of thefield trials.

Data and methods

The research methods used on all sites followed acommon strategy, and for reasons of simplicity wewill refer to this as Participatory Rural Appraisals(PRA), albeit with different levels of intensity. In eachcountry, villages were visited with multidisciplinaryteams, consisting of entomologists, economists, agro-nomists, and extension agents. Crop protection andextension experts were interviewed, and secondarydata and technical reports were collected on agri-cultural production, pests, and insecticide use. Ineach country, three or four representative and access-ible villages were selected together with local collab-orators, in the region most prone to grasshoppersand locusts (see Table 1 for details, and the mapin Figure 1). When possible, the meetings wereannounced a day beforehand, and all farmers wereinvited. On average, 27 farmers per village partici-pated in the discussions, conducted in the locallanguage. In all sites, the discussion followed an openguideline and started with an overview of the ecolo-gical and socioeconomic environment, followed byfarmers’ ranking of their constraints and pest prob-lems, concluding with an estimation of the frequencyof locust attacks and the resulting crop losses. Afterthe meeting, a few individual farmers were visitedfor clarification and verification. If the new tech-nology had not yet been demonstrated in the village,a demonstration or a participatory trial was organized.The farmers subsequently evaluated the technologyand compared it with other control methods. Finally,their willingness to pay for this technology wasassessed and compared with the expected cost of thebiopesticide.

In Niger, the LUBILOSA project had chosen theMaïné-Soroa subdistrict (arrondissement) of the Diffadistrict (département) (Figure 1), to conduct a large-scale trial, consisting of three 800 hectare plots in threeadjacent villages. In the beginning of August 1997,one plot was treated with the Metarhizium biopesticideand a second plot with a chemical pesticide (fenitro-thion), both by airplane, while a third plot or controlreceived no treatment. The area was visited for a PRA

one month later by a team of IITA scientists, officialsof the Niger Plant Protection Service (PPS), and ofthe agricultural extension service. After first visitingthe area around each treatment, group discussions withfarmers were organized in the three places, next to themillet fields of the trial. The owner of the field wouldusually participate, as well as the village headman andseveral council members, assisted by some interestedfarmers. Apart from the villages, the major ministriesand departments in Maïné-Soroa, Diffa, and Niameywere visited. The plant protection and agriculturalofficers of Maïné-Soroa were also invited to the treatedfields to discuss the results with the farmers.

In Mali, the biopesticide had previously been testedin Mourdiah and in the Dogon country, areas proneto grasshopper attacks (Douro-Kpindou et al., 1997),but only the Dogon area was retained because of thelocust control program of a local NGO. The area wasvisited for a PRA in June 1997 by a multidisciplinaryteam, consisting of IITA scientists, NGO field workers,and agents from the PPS. Four villages were selectedalong with those where the biopesticide had previouslybeen tested, based on heavy grasshopper problems anda good geographical distribution. Together with thevillagers, a village map was drawn and transect walkedwith key informants, leading to informal discussionswith farmers along the walk. In each village, theusual structured group interviews were conducted. Intwo villages, groups of women were interviewed ontheir role in agriculture and grasshopper control andtheir perception of pests. In two villages, individualfarmers were visited for more in-depth discussions.The team also visited the major agricultural servicesand projects in the area to discuss the potential of thebiopesticide.

In Bénin, the northern part of the Mono provincehas high potential for biopesticide use: the variegatedgrasshopper is a common pest here (Paraïso et al.,1992), and many farmers produce cotton, a cash cropthat provides access to pest control technology andcredit. After collecting secondary information aboutthe region, an interdisciplinary team executed a PRAin three villages during March and May 1997, the firstone lasting two days, the others each one day. Villagemaps were elaborated with the villagers, and the teamwalked over a transect of the territory with key inform-ants. Separate group interviews were conducted witholder men, women, and younger men, followed bytwo or three individual discussions with men andwomen. The team presented a summary of findingsto the village assembly for discussion, and the PRAconcluded in a demonstration trial and the planningof a collaborative research, the results of which arepresented elsewhere (Müller et al., 1999).

418 HUGO DE GROOTE ET AL.

Table 2. Characteristics of research villages in Maïne-Soroa (Niger).

Gel Adouage Kayeya Bara

Treatment Control Biological control Chemical control

with Fenitrothion

Number of inhabitants 500 150 500

Number of families 61 30 100

Land in millet (%) 20 30 <10

Millet production in good years >50 30 15

(sacks of 100 kg/hh)

Village self-sufficiency No No No

Non-agricultural sources of revenue Sales of wood, Sales of animals, Sales of animals

trade, labor in city work in Nigeria

Number of small ruminants in the village 1000 2000–2500 15000

Number of cattle in the village 200 1250 3000

The Senegalese grasshopper in Maïné-Soroa, Niger

Locusts and grasshoppers in Niger

In Niger, locusts and grasshoppers are consistent pestsof agricultural crops in many areas, and the countryhas developed an extensive control program. TheSenegalese grasshopper (Oedaleus senegalensis) is themost important species, and usually occurs with othergrasshopper species in what is known as the Saheliangrasshopper complex. In contrast with the sporadicoutbreaks of desert locust, these grasshoppers causemajor yield losses in millet on a regular basis. Thecountry has a well-trained Plant Protection Service(PPS), which has for many years received supportfrom the international donor community for training,capital, and working funds. Over the last 10 years,the PPS has been able to treat an average of 440,000hectares each year, including 300,000 hectares againstlocusts and grasshoppers (Direction de la Protectiondes Végétaux, 1997, with annual reports). The treatedarea is highly variable, and during locust invasionssuch as in 1988, more than 600,000 hectare can betreated.

Most of the locust and grasshopper control is doneby plane, although participation by the rural popula-tion has been encouraged through village brigades.These volunteers receive training in pest control andare provided with basic equipment such as sprayers.In the past, the brigades also received free pesticides,which they used to treat up to 50,000 hectares a year.Unfortunately, these brigades were created in responseto the needs of the PPS and its donors, not of thefarmers’ (De Groot, 1995). As a result, their structureand their activities are not sustainable without donor

support. Recently, some NGOs have also been organ-izing brigades, but the area treated is small comparedto the area treated by PPS sponsored brigades. The areatreated by all brigades combined is still only a fractionof that treated by plane.

Village brigades do actively involve the localfarmers, although so far, farmers have only contrib-uted labor. Unfortunately, the variable cost of onehectare treated by a brigade is much higher than onetreated by plane ($28 versus $4.6 in 1991, PLUR-ITEC/EDUPLUS 1993). Treatment with sprayersmounted on cars is still slightly cheaper, but manyareas are not accessible by car. Fixed costs, includingtraining and salaries, add another average of $20 perhectare treated (all prices are converted into dollarsusing the average exchange rate of that year). Clearly,these costs are not within the means of the farmersor even of the national government. The internationaldonor community covers most of the costs, and polit-ical and bureaucratic factors rather than economicanalysis dominate decisions in pest control.

The farming system of Maïné-Soroa

Maïné-Soroa has a typical Sahelian climate with anaverage yearly rainfall of 323 mm (average for 1995–1997). Diffa is the least populated district of Niger, andpeople make their living from livestock and agricul-ture, especially millet, and to a lesser extent, beans,and sorghum. Three villages were visited next to thetrial sites, one month afterwards (Table 2).

The people we visited were mostly Fulani, tradi-tionally nomadic herdsmen, who settled only recentlyto engage in crop production. Their villages are notvery structured and their main income is from live-

BIOLOGICAL CONTROL OF LOCUSTS AND GRASSHOPPERS IN WEST AFRICA 419

Table 3. Farmers’ perceptions of pests in Maïne-Soroa (Niger).

Name Gel Adouage Kayeya Bara

Principal pests Grasshoppers, Grasshoppers Grasshoppers,

caterpillars, head miners

birds

Millet production after 5–10 0–3 4

grasshopper invasion

(MT/household)

Number of invasions over the last 6 4 7

10 years

Damage to pasture (%) 80 50–80 >80

Willingness to pay per household 2–3 sacks 3 sacks 3 kg

stock. In most years, cereal production is insufficientand livestock sales are necessary, supplemented withsome income from labor in the city and sales ofwood. Inputs for livestock are regularly purchased,especially salt and vaccinations, but inputs for cropproduction other than manure are rare. As a result oflow rainfall and input use, yields are low and vari-able. Average millet yield in the district for 1994 to1996 was 353 kg/ha (Ministère de l’Agriculture et del’Elevage du Niger, 1996). Cereal production (milletand sorghum) is calculated at 149 kg/person, far shortof the 250 kg/person needed for self-sufficiency. Thenumber of cattle estimated by the villagers varies from4 to 41 per family.

Locusts and grasshoppers in Maïné-Soroa

Grasshoppers are generally considered the major croppest on millet, the major crop (Table 3). Others pestsmentioned are stem borer, millet head miner, and armyworms. The Fulani do not have a unit for area measure-ment, so crop loss estimation per hectare was notpossible, only per family. The harvest in a good year(with good rains and no grasshoppers) was estimatedat 1500 to 5000 kg/family of 5 to 15 people. Thiswould be slightly above the minimum requirement of250 kg/person/year. A heavy grasshopper infestationcan reduce this production to 300–1000 kg, or a lossof 80%. At $0.2/kg (average millet price in 1997), afamily could lose $400.

As a result of these potentially high losses, farmersexpressed a willingness to pay for grasshopper control.Answers were similar in the first two villages: 2–3 sacks (of 100 kg) and 3 sacks kg/family, with anestimated value of about $50. This is almost 10%of the expected harvest of 30 sacks in a good year.Assuming a yield of 600 kg/ha for those years, thearea can be estimated from their estimated harvest at5 ha. Dividing farmers’ willingness to pay by this area

result in $8/ha, which can be interpreted as the amountfarmers find reasonable to protect their crops againstlocusts. In the third village, however, farmers indicateda willingness to pay for the whole village, estimatedat $67. For an estimated 100 families, the averagebecomes $6.7 or 3 kg of millet per family, very lowcompared to the estimated losses.

The farmers’ evaluation of the biopesticide waspositive. They considered it superior to the chemicalpesticide because of its persistence of several weeks,compared to only a few days for the chemicals.

Economic analysis of locust control

The production of millet in the Sahel does not generatea high income: the average yield in Maïné-Soroaduring 1994–1996 was 353 kg/ha and, with an averageprice of $0.17/kg, generated an average of $60/ha.Estimates from the Ministry of Agriculture put theaverage crop value of Maïné-Soroa at $3 million peryear (for 90,000 people), and $7 million for the wholedistrict of Diffa (average for 1991–1995). Plant protec-tion expenses for the district in 1991 were estimated atabout $0.5 million, or roughly 7% of the crops’ value.In other words, at least 7% of crop losses need to beavoided to make the treatments cost effective. Directmeasurements estimate the average yield loss on milletcaused by locusts at 15% (Krall et al., 1995), much lessthan farmers’ estimates but higher then the interven-tion cost. Unfortunately, no data are available on theefficacy of plant protection measures to compare costswith benefits.

Discussions with resource persons

We interviewed people in research institutes, plantprotection agencies, extension services, regionaladministrations, and projects. Apart from the scient-ists, who doubt that any pest control could ever be

420 HUGO DE GROOTE ET AL.

Table 4. Agriculture in the Dogon country (Mali), villagers’ estimates.

Koa Golokanda Yawa Nombori

Households/village 20 37 45 101

ha cultivated/hh 10 5–15 12 2–15

hh with oxen (%) 100 55 75

% of land in millet 1 (50%) 1 (75%) 1 (>80%) 1 (75%)

Sales (field crops) 1/3, especially Only peanuts (40%) None Peanuts,

sorghum bambara nut

Sales (horticulture) Onions, most Onions, most All

other crops other crops

Yield of millet (kg/ha) 1000 480 200–600 100–500

Price of millet 70 37.5 (at harvest) 80

(FCFA/kg) 90 (at survey time, 100

August)

economical in the Sahelian cereal production, thegeneral perception was that locusts are such a majorproblem that the government has to act to preventmajor losses that result in famine and rural emigra-tion. For our respondents, economic analysis is ofminor importance compared to social considerationsand political factors. At times of locust outbreak, thegovernment is under strong pressure to react. Thepest is very visible, and farmers put pressure on localextension and PPS officers and village chiefs, andthe pressure moves through the district and provincialadministrations to the national level. At the same time,villagers and their relatives in the city exert influenceon elected representatives in town councils and in theparliament. Politicians and administrators, who do notwant to be perceived as insensitive, need to show someaction, even if it is not effective. And since the efficacyof locust and grasshopper control is extremely difficultto measure, any action is better than no action at all.

Further research

The attitude towards biological control in Niger isquite positive. Most people, farmers as well as PPS andMinistry of Agriculture officers are interested; they areopen to it and are willing to give it a chance. The studyalso showed that although farmers are willing to paysomething for locust control, these amounts will besmall because of their very limited income. Even whenbiological control of locusts would overall be costeffective, it is unlikely that farmers would be willingor able to pay its full cost. In the best possible scen-ario, farmers would make a substantial contribution,with the rest of the cost covered by the government,up to the level of economic feasibility. The challenge

to the LUBILOSA project is to develop a use strategyin which farmers can pay their contributions, to besupplemented by the international donor communitywith technical support of local services.

Maïné-Soroa, however, is not a good target area fordeveloping such a strategy, even though grasshopperinfestation is high and relatively predictable. Humanpopulation density is low, farms are spread out farand wide, crop production is not the main activityhere, and extension services are spread very thin. Theproject should move to an area with a higher popula-tion density, where farming is the major occupation.This would avoid having to treat fallow, and exten-sion and distribution of biopesticides would be a lotcheaper.

The Sahelian grasshoppers in Dogon Country,Mali

The farming system

The Dogon live in the eastern part of the Mopti admin-istrative region, with a typical Sahelian climate andone rainy season with 350 to 750 mm of rainfall.Average rainfall has decreased over recent years, andthe region suffers from chronic deficiencies in basicfood production, especially cereals (DNSI-PADEM,1994). Population density is low, 15.6 people per km2,reflecting the harsh living conditions, which pushpeople into emigration. Villages are scattered, andthe visited villages varied in size from 20 to 101households.

The economy of the Dogon country is based onagriculture. The households consist of an extended

BIOLOGICAL CONTROL OF LOCUSTS AND GRASSHOPPERS IN WEST AFRICA 421

Table 5. Tanking of major pests reported on field crops by village (Dogon country, Mali).

Koa Golokanda Yawa Nombori

Locusts and 1 (on cereals, 1 (on millet) 1 1 (from 88–90)

grasshoppers not on legumes)

Blister beetles 2 3 3

Lepidoptera 3 (on peanuts) 3 (but 1 on 2 (ear borers, 1 (90–96)

onion) miners)

Coleoptera 2 (millet)

Striga 4

Rodents 4

Monkeys 4

Yield loss after locust 60–100% 23/24 2/3 Almost

attack everything

Locust history of last 10 4 medium bad 1996 was good, 1988 to 1990

years years, 1 year the other years were very bad

very bad (1995) bad

family and are large (average size in the Bandiagarasubdistrict is 12 people). Villagers estimate that house-holds have between 2 and 15 ha of land in cultivation.Apart from the household fields, individuals can havesmall private plots, on which they are allowed to workone or two days a week. The group discussions withfarmers in 4 villages showed that millet, the majorcrop, takes up between 50 and 80% of the cultivatedland (Table 4). Other important crops are sorghum,fonio, cowpea, peanuts, and bambara nut. Millet isstrictly for home consumption, but peanuts, and toa lesser degree, sorghum and bambara nut, are sold.Farmers complain that their production can no longerfeed the population, and statistics indicate a cerealdeficit of 42% (DNSI-PADEM, 1994). Horticulturein the dry season becomes increasingly important forgenerating cash, especially onions, which have a longtradition in the area.

During the survey, farmers estimated their milletyields vary between 100 kg/ha and 1000 kg/ha. Thedepartment of agricultural statistics’ estimates for1993 to 1995 was 447 kg/ha (DNSI, 1996). Farmersestimate the millet price between $0.07 and $0.17/kg.Prices in Mopti at the time of the survey were at thehigh end of that range, and stayed at around $0.17/kgeven after the 1997 harvest. At the average price of$0.12/kg, the value of millet production can be esti-mated at $50/ha, and even at the highest price a hectareof millet would only generate $80.

Pests

Villagers generally considered locusts and grasshop-pers as their major pests, except for one village where

it was blister beetles (Table 5). The other major pestsmentioned were beetles, stem borers, and head borers.Farmers estimate the yield reduction caused by locustssomewhere between 60 and 100%. The locusts dodamage on most farms, although not on all fields:fields closer to fallow are reportedly attacked more.The damage due to locusts and grasshoppers is veryvariable from year to year and from village to village.

In the past, villagers controlled locusts by beatingthem with sticks or by digging trenches to bury them.Farmers complain, however, that the locusts changedtheir behavior in recent years, “they are a lot smarternow,” so there are few alternatives to the use ofchemical pesticides.

A local church-supported NGO, PDAD (ProjetDiocésain d’Agriculture Durable), has a locust controlprogram, in which all villages visited participated. Inthe past, villages had to provide the labor for thevillage brigades, plus a cash contribution of 20,000FCFA per year. The NGO then provides the pesti-cides and the spraying equipment. From 1997 on,the villages are asked to pay 25% of the cost of thechemicals.

The farmers who had attended the demonstra-tion trials of the biopesticide reacted positively. Mostfarmers recognized its comparatively slower action butacknowledged its longer persistence. They declared amodest willingness to pay. Although not all villagersagreed, a figure of $8/ha was often mentioned, roughlyhalf of the production cost of the biopesticide, but 10to 16% of the crop value. Some people declared theycould not pay this, or only if they had the cash, whileothers offered to pay up to $17, even $32 per hectare.The willingness to pay is clearly linked to cash avail-

422 HUGO DE GROOTE ET AL.

Figure 2. The agricultural calendar as developed by the villagers of Hontoui, Mono Province.

ability, strongly influenced by income, which againis strongly influenced by onion production. Access tocredit could also play an important role here.

Different types of hand held sprayers werediscussed, but the results were inconclusive. The ULVformulation requires expensive batteries, but does notneed water while the Emulsifiable Concentrate (EC)formulation does not need batteries, but substantialamounts of water that need to be tranported to the field.

Locust politics

Locust swarms can be very spectacular and a field canbe devastated in a short time, so farmers can bringthis pest easily to the attention of government officials.During our discussions, government officials consist-ently expressed great concern for the farmers whosefields were attacked by this pest. As in Niger, therewas a feeling that something really had to be done, butmore out of social concerns than based upon economicconsiderations. This is influenced by Mali’s recentchange to a multi-party democracy, with free presid-ential and parliamentary elections, and its move to amore decentralized government in which local offi-cials are elected instead of appointed by the centralgovernment.

Further research

Grasshoppers and locusts are clearly major problems,at least in the villages interviewed. Unfortunately,the value of the crop is quite low, so treatments areonly economically justified at high yield losses. Morestructured and quantitative research is needed on arepresentative sample to estimate yield losses and linkthem to insect population densities to determine theintervention threshold.

Contrary to a previous survey (Stonehouse et al.,1997), it was found that farmers are willing tocontribute to locust control. These potential contri-butions, although not negligible, will generally not

cover the cost of the biopesticide, or any other pesti-cide for that matter. Tests need to be conducted tosee if doses can be reduced without losing efficacy,but some subsidy will most likely be necessary. Fortu-nately, the local NGO, PDAD, is already subsidizinglocust control. Moreover, their German donor organi-zation Misereor has strongly encouraged them to lookfor alternatives to chemical control, so collaboration isclearly indicated. Further study needs to address thesocially optimal subsidy level.

Most of the crop losses caused by locusts occurin the households’ millet fields, not on individual oron the more intensive onion fields. Locust control, onthe other hand, is organized through village brigades.Unfortunately, the brigade members are typicallyyoung men who hold little power in village politics.Moreover, they are likely to emigrate to the city, andreplacements need to be found and trained. Therefore,village brigades should have some supporting structureor committee with older, more stable farmers. Thiscould be supported by the NGO, which has a solidextension organization with motivated workers. Thismodel could be extended with several other organiza-tions that are active in the region and showed someinterest.

The variegated grasshopper in the MonoDepartment, Bénin

The farming system

The Mono Department is situated in the derivedsavanna of southwestern Bénin. The area has ahigh population density of 169 inhabitants per km2

(INSAE, 1998), growing at a rate of 3.2% per year.The rainfall pattern is bimodal, with an average yearlyrainfall between 1000 and 1200 mm. In the firstseason (March–July), farmers grow mainly maize,cowpea, and peanuts (Figure 2), and during the second,

BIOLOGICAL CONTROL OF LOCUSTS AND GRASSHOPPERS IN WEST AFRICA 423

Table 6. Garmers’ ranking of the four most important field pests, by village (Monoprovince, Benin).

Ranking in order of Hontoui Eglime Zouzouvou

importance

1 Grasshoppers Rats and aphids Snails

2 Crickets Aphids

3 Parridges Grasshoppers Grasshoppers

4 Rats Caterpillars Stemborers of maize

short rainy season (September–November) they growmostly cotton, often planted between the maize rows.Cassava is planted in the first rainy season but onlyharvested after the second rainy season. Farmersusually have two to three fields at a time, with oil palmsmixed in with the crops. When the soil is depleted, thefield is left in fallow except for the palm trees. Thefarmer then moves on to an old palm orchard, fells thetrees for palm wine production and clears the land toplant crops.

The variegated grasshopper

The variegated grasshopper (Zonocerus variegatus) isthe only serious grasshopper pest in the humid areasof West Africa. It can attack almost any crop, butcauses most damage to cassava. It is a non-migratorypest with a preference for humid lowland forests,where it is restricted to the sunlit edges and clearings(Modder, 1994). From the 1950s onward, deforesta-tion and agricultural intensification opened new areasfor this grasshopper species, and its economic impactis increasing (Modder, 1994).

In all villages, the variegated grasshopper wasranked among the three most important pests (seeTable 6). Other pests, mentioned in at least twovillages, were aphids, rodents, caterpillars, and thelarger grain borer. In the group discussions, villagersremarked that although the grasshoppers have alwaysbeen around, they had become a major problem onlyover the last five years. They described how grasshop-pers typically emerge at the end of the first rainy seasonto reach a peak at the end of the second rainy season.The population then slowly decreases over the dryseason to disappear quickly at the beginning of therainy season (Figure 2). Contrary to a study in Nigeriawhere farmers understood the egg laying behavior andthe life cycle of the grasshoppers (Page and Richards,1977), the farmers in Mono have little knowledgeof grasshopper biology. Most farmers assumed thatgrasshoppers reproduce through eggs, although noneof the villagers in the group discussions had ever seenthem. Similarly, in all villages concerned, farmers

considered the larvae and the adult grasshoppers as twodifferent species. They do observe a high mortality atthe end of the main rainy season, which they attributeto the rainfall.

Damage and pest control

In all three villages of the study, farmers observeddefoliation by the variegated grasshopper of all plantsexcept for the neem tree. They noticed that grasshop-pers first eat the leaves and continue with the bark,especially of cassava, and kill the seedlings. Thedefoliation decreases yields, but mostly in the secondseason when the grasshoppers are abundant. Cropsmost affected are thus the maize planted in the secondseason and especially cotton. Some farmers madeindividual estimates of yield losses, such as 90%for cowpea, 30% on maize and cotton. Estimates oflosses varied widely between and within groups, andmany farmers were hesitant to give estimates, so noconsensus could be reached. Apart from crop losses,farmers also consistently mentioned the loss of seed-lings and the resulting cost of replanting, in both seedand labor.

Since grasshopper density is low in the first rainyseason, yield loss to first season crops, particularlycassava, is rare. When grasshoppers start to attackcassava, the plant is already older and will shedsome leaves for the dry season anyway. Farmerspoint out, however, that grasshopper attacks have amajor impact on the quality of the tuber. Women inall villages mentioned that the color changes fromwhite to pinkish, that the tubers change structure andbecome watery, which hampers processing and there-fore decreases its market value. Finally, bark loss incassava makes stems useless for cuttings.

Since the grasshopper was not really a problemuntil recently, farmers have not developed any controlmethods. Some farmers tried cotton pesticides, whichthey found not to be very effective against grasshop-pers. They generally use two kinds of sprayers: flitguns, which are manual, bicycle pump type sprayers(external air-shear nozzle sprayer) designed for house-

424 HUGO DE GROOTE ET AL.

hold spraying, and spinning disk sprayers, which arebattery driven and use Ultra Low Volume (ULV) appli-cations in particular for cotton. Many, but not allfarmers in this area prefer the flit guns for treating theircrops. Advantages cited are lower initial cost (less than$2 against about $60 for the spinning disk sprayer),elimination of batteries, and a slower pace of applic-ation, which increases the accuracy of spraying lowdoses.

Institutional support and political pressure

During discussions, plant protection and agricul-tural extension officers indicated that the variegatedgrasshopper is a very visible pest, large, and colorful.Therefore, it attracts relatively more attention thanother pests, which in turn helps farmers to pressureofficials and elected local politicians in supportinggrasshopper control actions. Although there is notmuch evidence or studies on crop losses, this pressureresulted in several grasshopper control campaigns,based on donor support. At the moment, this supporthas decreased substantially, and government servicessuffer from a severe shortage of operational funds.

Further research and participatory learning andaction

In all villages, the village assembly concluded thatthe variegated grasshopper was a serious problem andthat villagers would appreciate a control method suchas the biopesticide. They were, however, hesitant toestimate how much they would be willing to pay, nothaving seen its efficacy. Therefore, a demonstrationtrial was organized in the first survey village. A highlyinfested field was sprayed with the biopesticide, andin two subsequent visits, one and two weeks later, theresults were discussed with the farmers. The farmersobserved the slow but efficient killing of grasshop-pers and expressed an interest in further testing. Inthe other villages, it was too late in the season and noinfested fields were available, but given the seriousnessof the grasshopper problem, they were still interestedin trying out the biopesticide.

The variegated grasshopper does not migrate much,so treatments could be organized and financed on thevillage level. The organization of a village brigadewas proposed by the project and accepted by thevillage, who selected eight volunteers. This brigadereceived training, and subsequently the scientists andthe villagers discussed the research agenda. The rela-tively high cost of the product did not seem to deterthe farmers, especially since the grasshoppers usuallyconcentrate in the field, especially at earlier stages.Still, to reduce costs, it was agreed to spray the earlystages, and to try out lower doses. The scientists, aware

that the grasshoppers hatch in the bush, suggestedspraying those areas, which was accepted. The farmerssuggested testing flit guns, which are widely available,cheap, and do not use batteries. This was accepted,although it took an effort to convince some scientists,who objected to the poor quality of the equipment,especially the large and uneven droplets they produce.

The participatory research was continued duringthe following year in the two villages that had heavygrasshopper infestations, and its complete resultsare presented elsewhere (Müller et al., 2000). Insummary, two different timing strategies (preventiveand curative), three different doses (2, 20, and 50 g/ha),and two different sprayers (flit gun and spinningdisk sprayer) were tested in farmers’ fields. Farmerspreferred the preventive treatment with a medium dose(20 g/ha), applied with a spinning disk sprayer. Half aday of training for a village brigade was found suffi-cient to enable them to identify egg-laying areas andthen apply the biopesticide.

Finally, farmers discussed the organizational struc-ture they preferred for disseminating the technology.They proposed that the biopesticide producer wouldsell the product directly to the village association, andprovide credit to the association. The village brigadewould treat the grasshoppers, and be reimbursed by theaffected farmers. This strategy will be tested as soon asthe product becomes commercially available.

Discussion and conclusion

In all regions visited, farmers perceive locusts andgrasshoppers as a major pest problem. Where farmerssaw a demonstration of the biopesticide, the responsewas generally positive. The slow speed of kill,while clearly observed, was not usually considered aproblem. Its persistence, on the other hand, was seenas a major advantage. The few negative responses wererelated to the small numbers of dead insects observedin the field. Because of the slow kill, birds can eatthe sick or dead insects relatively unnoticed, whileafter a chemical treatment the cadavers spread all over.Although farmers, especially in the Sahel, are verypoor, they consistently express a small but signifi-cant willingness to pay for locust control. No efficientpesticides against locusts are currently available on thelocal markets, so hitherto this willingness has not beenexpressed into actual purchases.

At the technical level, PPS and extension agentsgenerally share the farmers’ positive opinion of thebiopesticide. They do not think, however, that farmershave the means and the interest to purchase this tech-nology. They feel very strongly that it is the duty of thegovernment and the international donor community

BIOLOGICAL CONTROL OF LOCUSTS AND GRASSHOPPERS IN WEST AFRICA 425

to do so. Governments, however, only spend asmall amount on locust control despite strong polit-ical pressure, since they can rely on foreign donors.These donors are now increasingly reluctant to financeprograms that carry environmental risks (Louis Bergerand Associates, 1991) and health costs (Houndekonand De Groote, 1998), so biopesticides have a poten-tial advantage. Production costs at the pilot plantare still high ($11 or $22/ha, respectively, for thetypical doses of 50 or 100 g/ha, Cherry et al., 1999)but the price should be reduced substantially oncecommercial production starts. The product faces stiffcompetition from chemical pesticides, which are notonly cheaper, but also benefit from strong promotionalefforts from their producers influencing the decisionsin the national plant protection services.

Potential implementation pathways were discussedintensively at a series of annual workshops involvingLUBILOSA project staff, PPS collaborators, anddecision makers in Cotonou (1996), Niamey (1997),and Bamako (1998). As a result, the best optionseems to transfer the production technology to privateproduction companies. These companies need to haveexpertise both with the production of biological pesti-cides and with the African pesticide market, and goodcontacts with donor agencies. Progress will thereforedepend on an integrated approach involving furtherdevelopment of the technology as well as motivatingpotential buyers (Lomer et al., 1999).

There are several important ramifications to thisapproach. Perhaps most importantly, the biolog-ical product enters the standard pesticide registrationprocess, allowing the countries involved a fully inde-pendent review of the safety and environmental risksassociated with the biopesticide prior to accepting itslarge-scale implementation. At the time of writing(July 2000), registration has been granted in SouthAfrica, and provisional clearance for sale has beengranted by the CILSS CSP (Conseil de Securité desPesticides). Intellectual property rights issues alsobecome important, as the countries, particularly Niger,supplied the fungal germplasm and participated in theresearch and development process and should benefitfrom any royalty payments arising from the sale of theproduct.

Future development needs to focus on three issues:when is biocontrol cost-effective, how can the farmers’contributions be captured, and what structure needs tobe put in place to combine their contributions withthose of donors, extension services, and the privatesector. Although many gaps remain in our under-standing, some possible scenarios are emerging. Inthe humid areas, where the variegated grasshopperis an important but non-migratory pest, biocontrolof the locust should be financed and carried out

by the farmers themselves. The amounts needed aresmall compared to their cash income and farmers are,in the Mono at least, familiar with basic pesticideuse. A local committee or brigade can be organizedand trained, preferably in connection with the cottonproducers’ village association. This association canthen provide credit, as it does already for cotton inputs.Some technical and organizational aspects still remain,but those should be solved during the next phase ofthe participatory research. The plant protection serviceis capable of providing training, if funds are madeavailable.

In the Sahel, farmers’ income is very low, andcash availability is an important constraint. Moreover,locust attacks are highly unpredictable, so it is unlikelythat the private sector will carry a suffficient stockof biopesticides and that individual farmers will buyit. Moreover, there is always the risk that the PPSprovides free pesticides, ruining the market. Thepublic sector needs to be involved, but here the situ-ations in Mali and Niger are substantially different. InMali, a number of NGOs and projects have come toplay a major role in providing extension, either directlyor by supporting government services. In Niger, on theother hand, the government is still very much directlyengaged in migratory pest control. Decision making inthis situation is very complex, and any project needs toadvance carefully taking into account the aspirationsand capacities of the key decision makers.

Scenarios for the Sahel necessarily include subsid-izing biopesticides. The simplest scenario is toconvince donors to purchase biopesticides as a substi-tute for chemical pesticides, and use the existing PPSstructures to distribute them. The PPS are well quali-fied to provide the service, organization, and trainingto the village brigades, if they have the funds. Thisscenario could be pursued in Niger. A second optionis to promote biocontrol with the NGOs, and toprovide them with information and training to incor-porate biocontrol in their activities. In this context,LUBILOSA’s heavy investment in training of PPSofficers is likely to pay off, as NGOs may be able tocontract government officers as resource persons. Itis important that the interested NGOs have sufficientindependent funding, such as for example, the NGO inthe Dogon country. A third option would be a directprice intervention, in which subsidized biopesticideswould be sold directly to farmers or farmers’ groups.

To obtain optimal results, care should be given todesign a proper subsidy policy, based upon clearlyspecified criteria. To assist the decisionmaking processin locust management, more quantitative informationis clearly needed. Surveys of a representative sampleof farmers in the three countries are needed to providebasic data, such as frequency of attacks and crop

426 HUGO DE GROOTE ET AL.

losses. More information is needed on the risk of locustand grasshopper attacks as perceived by farmers, howimportant those attacks are to farmers, and how muchthey are willing to pay for control measures. Furtherstudies need to establish the relationships between thepests, the damage they cause, and the resulting croplosses. The combination of these data will allow foran estimation of the expected economic loss due tolocusts and grasshoppers, as well as the variance andthus the risk. At the same time, data are needed onthe efficacy of different treatments and strategies, tocalculate the expected benefit of these strategies andcompare it with their cost.

Finally, this study shows how the participatoryapproach can pool the capacities and resources offarmers, entomologists, and social scientists together.The technology was suggested, developed, and testedon its technical merits by entomologists; social scient-ists indicated where it could be economically feasibleand socially acceptable; and farmers tested the applic-ation methods they found interesting, and developedthe use strategies. Working in different countries andecologies showed the need for flexibility. In Niger,because of the aerial application method and thelogistical difficulties, the consultative approach wasindicated. The approach was sufficient to show that,although the technology was technically feasible, insti-tutional support was poor and the technology wasunlikely to be economically feasible. In Mali, thanksto the strong presence of an NGO, the research couldpursue a more collaborative approach. This approachresulted in testing and evaluation by the farmers, andthe positive results indicated a potential use strategy. InBénin, neither farmers or institutions had much exper-ience with locust control, so a more intensive approachwas necessary, and the proximity of the site to theresearch station made frequent visits and a collegialapproach possible. This resulted in a participatorylearning and action process, and the development of anappropriate use strategy. Our experience indicated thatthis would not have been possible in a less intensiveapproach.

Over all sites, the flexible participatory approachallowed to capture farmers’ perceptions on locustsand grasshopper problems, as well as their evalu-ation of the new technology. Thanks to the exchangeswith farmers and other stakeholders, potential usestrategies were developed and policy recommenda-tions formulated. Finally, the approach helped toidentify constraints and potential bottlenecks, and toformulate further research and participatory action.

Acknowledgments

The authors thank the farmers for their participa-tion and guidance in this research; LUBILOSAproject coordinator Juergen Langewald for his supportand enthusiasm in incorporating the participatoryapproach; the plant protection and agricultural officersin the three countries visited for their collaboration;Victor Manyong, James Gockowski, and Steve Franzelfor reviewing earlier versions of the paper and fortheir appreciated comments and suggestions; and thegovernments of Canada, Switzerland, The Nether-lands, and Great Britain for their financial supportof this project, which is implemented by a networkof collaborators from CABI Biosciences (formerlyIIBC: International Institute of Biological Control),IITA (International Institute of Tropical Agriculture),CILLS (Comité Permanent Interetats de Lutte Contrela Secheresse), and GTZ (Deutsche Gesellschaft fürTechnische Zusammenarbeit).

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Address for correspondence: Hugo De Groote, InternationalMaize and Wheat Improvement Centre, CIMMYT, P.O. Box25171, Nairobi, KenyaPhone: +254-2-524600; Fax: +254-2-522879;E-mail: [email protected]