Whitefly and whitefly-borne viruses in the tropics : Building a ... - cgiar

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Malawi (40%) believe that the whitefly/TYLCV incidence is higher when it is dry and hot, while others (30%) said they experience most problems when it is wet and cold. The opinions of the remaining producers were scattered between the remaining combinations of dry, moderate, wet and hot, moderate, and cold weather. Producers gave estimation of the costs involved in crop protection measures (see below). Costs estimated by producers in control of whitefly/TYLCV complex per season of tomato production US$ % producers 0-49 26 50-99 16 100-199 19 200-299 14 300-400 9 >400 16 Many producers (42%) had not received recommendations on management practices for whiteflies. Those who had received advice obtained it from various sources: 34% received recommendations from technical advisors, 15% from other vegetable producers, 6% from family members or neighbours and 3% from sales agents. Most producers (90%) managed the whitefly/virus problem by means of synthetic pesticides, 4% by cultural means and 6% practiced no control at all. Other control methods such as legislative measures, natural insecticides (e.g., botanicals and biopesticides), biological control and the use of resistant varieties, were not reported. Pesticide use The decision on what insecticide to apply and when was made by the producer himself in 58% of the cases, by technical advisors (29%), sales people (3%) or a family member (2%), while 7% did not use insecticides on their farms. Half the producers (52%) applied insecticides as a preventive measure, while 33% applied them when damage was observed and 5% applied insecticides according to the calendar. Few producers (5%) reported making more than 10 insecticide applications per season, while 4% made 9-10 applications, 37% of the producers made 5-8 applications, 40% made 1-4, and 14% applied no insecticides to manage the whitefly/ disease problem. The insecticides most widely used in the management of the whitefly/ TYLCV problem in Malawi include: fenitrothion, malathion and dimethoate (organophosphates); cypermethrin and lambda-cyhalothrin (pyrethroids); carbaryl and sevin (carbamates). Farmers were ignorant of the fact that chemicals with the same active ingredient often are sold under various trade names and they therefore risk using the same active ingredient throughout, rather than alternating with others. The use of fungicides was common because producers confused TYLCV symptoms with blight. Miticides such as dicofol were used also in an attempt to control whiteflies but EXTOXNET (1998) reports that this chemical has little effect on insects. Strengthened Research Capacity Scientists from ICIPE trained and accompanied the national scientists during the beginning of the survey. The project has equipped national scientists with a better understanding of the severity of whitefly-related problems in the country’s vegetable production. New information on the status of whiteflies and the whiteflytransmitted viruses in tomato now is 155
available. Understanding our producers’ perceptions and practices in relation to whitefly problems has been a significant achievement of this project. 156 Conclusions Whitefly/TYLCV “hot spots” in Malawi include Dedza, Mzimba, Thyolo and Ntcheu. In both Dedza and Ntcheu, several farmers reported having abandoned their tomato crops at least once due to whiteflies/TYLCV. For this reason, these two areas should be targeted for further research in the second phase of the project. B. afer, followed by B. tabaci, is the prevalent whitefly species in most parts of the country and the most widespread parasitoid was E. sophia. Although many producers recognized whiteflies and TYLCV, they often confused TYLCV symptoms with those of other pest and disease or nutrient deficiencies. Producers also were confused about the climatic conditions that trigger outbreaks of whiteflies and TYLCV. Incidences of TYLCV in Malawi were not as high as in neighbouring Tanzania. Only 6% of the surveyed farms had TYLCV incidence above 25%. Although TYLCV incidences were generally low, the disease was Whiteflies and Whitefly-borne Viruses in the Tropics encountered in all surveyed areas, indicating that the whitefly/TYLCV complex is a potential threat to Malawi’s vegetable production. References EXTOXNET (Extension Toxicology Network). 1998. Pesticide information profile, 3 Nov 1998. Available in: http:// pmep.cce.cornell.edu/profiles/ extoxnet/carbaryl-dicrotophos/ dicofol-ext.html (Accessed 2 May 2000) Löhr, B. 1996. The citrus woolly whitefly in eastern and southern Africa: Distribution, indigenous natural enemies and control strategies. In: Procs. International Society of Citriculture. Vol. 1, p. 619-624. Mkanda, F. X.; Kainja, S.; Kalindekafe, M.; Chavula, G. M. 1995. Malawi: Greenhouse gas inventory and assessment of climate change vulnerability. Interim report on climate change country studies, March 1995. US Global Change Research Information Office (GCRIO). Available in: http:// www.gcrio.org/CSP/IR/ IRmalawi.html (Accessed 11 May 2000) Swanson, M. M.; Harrison, B. D. 1994. Properties, relationships and distribution of cassava mosaic geminiviruses. Trop. Sci. 34:15-25.
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About the Partners CIAT The Interna
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Centro Internacional de Agricultura
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Chapter 4 Whiteflies and Whitefly-b
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Chapter 6 Whiteflies and Whitefly-b
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Contents Page Foreword vii Introduc
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Contents Chapter SECTION THREE Whit
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Foreword This book is the product o
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Introduction Introduction The Probl
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Introduction In addition to the yie
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Introduction in pesticide use in La
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Introduction annual crops, especial
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Introduction Plant Resistance contr
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Introduction Otim-Nape, G. W.; Bua,
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SECTION ONE Whiteflies as Vectors o
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Introduction CHAPTER 1.1 Introducti
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Introduction diseases than is cassa
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Introduction Sub-project on Whitefl
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Introduction References Aritua, V.;
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Introduction Thresh, J. M.; Otim-Na
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Ghana 1997, on 80 farms. These incl
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Ghana (6.2%), Bakentenma (5%) and K
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Ghana Legg, J. P.; James, B. D. 199
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Benin Northern guinea savannah Sout
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Benin or disease problem, the main
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Nigeria CHAPTER 1.4 Nigeria Introdu
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Nigeria TMS 30572 (18.8%) and TMS 3
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Nigeria FAO (Food and Agriculture O
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Cameroon protocol, to enable valid
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Cameroon Farmers undertook various
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Cameroon Robertson, I. A. D. 1987.
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Uganda between November 1997 and Ja
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Uganda environment, host plant heal
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Uganda local varieties. Assessments
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Uganda Harrison, B. D. 1987. Proper
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Kenya Recent epidemiological studie
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Kenya respective diseases were reco
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Kenya Bock, K. R. 1983. Epidemiolog
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Tanzania CHAPTER 1.8 Tanzania Intro
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Tanzania Adult whiteflies were more
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Tanzania loss) to assess yield loss
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Tanzania Legg, J. P.; Raya, M. 1998
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Malawi Increased Biological Underst
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Malawi Physiology and Ecology in th
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Madagascar Tanzania Madagascar Moza
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Madagascar surprising, particularly
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Diversity of African Cassava Mosaic
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Sweetpotato Virus Disease in East A
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Factors Associated with Damage CHAP
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Factors Associated with Damage Mean
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Factors Associated with Damage % SP
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Factors Associated with Damage thro
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Factors Associated with Damage Gedd
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Conclusions and Recommendations col
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Conclusions and Recommendations Mal
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Conclusions and Recommendations Mpi
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Page 122 and 123: Conclusions and Recommendations con
Page 124 and 125: Conclusions and Recommendations (2)
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Page 128 and 129: SECTION TWO Whiteflies as Pests and
Page 130 and 131: Introduction CHAPTER 2.1 Introducti
Page 132 and 133: Introduction Czosnek, H.; Navot, N.
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Page 136 and 137: Sudan Table 1. Reproductive host pl
Page 138 and 139: Sudan Historically, Sudan has been
Page 140 and 141: Sudan Only 10% of producers reporte
Page 142 and 143: Sudan Conclusions The work conducte
Page 144 and 145: Kenya CHAPTER 2.3 Kenya Introductio
Page 146 and 147: Kenya Increased Biological Understa
Page 148 and 149: Kenya Samples of 10 plants per fiel
Page 150 and 151: Kenya Table 4. Maximum incidence (%
Page 152 and 153: Kenya Seventy-nine percent of tomat
Page 154 and 155: Kenya under Phase 2 of the TWF-IPM
Page 156 and 157: Tanzania CHAPTER 2.4 Tanzania Intro
Page 158 and 159: Tanzania The reproductive host plan
Page 160 and 161: Tanzania Geographical range of whit
Page 162 and 163: Tanzania Local names given to white
Page 164 and 165: Tanzania Nono-Womdim, R.; Swai, I.
Page 166 and 167: Malawi levels of infestation by the
Page 168 and 169: Malawi Table 3. Maximum incidence (
Page 172 and 173: Tomato Yellow Leaf Curl Virus in E.
Page 178 and 179: Conclusions and Recommendations CHA
Page 180 and 181: Conclusions and Recommendations (Fi
Page 182 and 183: Conclusions and Recommendations Cen
Page 184 and 185: Conclusions and Recommendations the
Page 186 and 187: SECTION THREE Whiteflies as Vectors
Page 188 and 189: Introduction CHAPTER 3.1 Introducti
Page 190 and 191: Introduction especially for export.
Page 192 and 193: Mexico CHAPTER 3.2 Mexico Introduct
Page 194 and 195: Mexico Culiacán, Sinaloa, in north
Page 196 and 197: Mexico Table 2. Virus survey of tom
Page 198 and 199: Mexico results of the molecular bio
Page 200 and 201: Mexico Strengthened Research Capaci
Page 202 and 203: Mexico López, R. 1996. Experiencia
Page 204 and 205: Guatemala 1960s, and at this time t
Page 206 and 207: Guatemala Table 2. Results of white
Page 208 and 209: Guatemala Table 5. Cropping systems
Page 210 and 211: Guatemala contemplated in this prel
Page 212 and 213: El Salvador CHAPTER 3.4 El Salvador
Page 214 and 215: El Salvador During the course of th
Page 216 and 217: El Salvador markets: common bean, m
Page 218 and 219: El Salvador Current Status of White
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Honduras Copan Ocotepeque Santa Bá
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Honduras Table 3. Biotyping of whit
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Honduras References Caballero, R. 1
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Nicaragua Nueva Segovia Madriz Este
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Nicaragua Lowlands of Nicaragua. Th
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Nicaragua Region VI is a main horti
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Costa Rica CHAPTER 3.7 Costa Rica I
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Costa Rica Table 1. Characterizatio
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Costa Rica Castillo, J. 1997. Movim
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Panama Bocas del Toro Chiriquí Ver
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Panama Gámez, R. 1970. Los virus d
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Haiti Grande-Anse Sud Grande-Anse S
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Haiti collaborators in this project
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Cuba Ciudad de la Habana Pinar del
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Cuba Table 3. Comparative homologie
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Cuba project provided three keynote
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Dominican Republic CHAPTER 3.11 Dom
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Dominican Republic monoclonal antib
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Dominican Republic Strengthened Res
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Reproductive Crop Hosts of Bemisia
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Biotypes of Bemisia tabaci CHAPTER
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Biotypes of Bemisia tabaci For this
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Biotypes of Bemisia tabaci 100 99 B
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Biotypes of Bemisia tabaci biotype
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Biotypes of Bemisia tabaci Table 2.
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Biotypes of Bemisia tabaci Already
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Conclusions and Recommendations CHA
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Conclusions and Recommendations gre
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SECTION FOUR Whiteflies as Pests of
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Introduction CHAPTER 4.1 Introducti
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Introduction control, due to resist
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Introduction Posada, L. 1976. Lista
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Colombia and Ecuador B biotype B. t
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Colombia and Ecuador assistants and
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Colombia and Ecuador and squash. On
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Colombia and Ecuador Table 2. Main
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Colombia and Ecuador Table 6. Patte
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Insecticide Resistance in Colombia
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Conclusions and Recommendations CHA
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Conclusions and Recommendations res
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Conclusions and Recommendations rot
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SECTION FIVE Special Topics on Pest
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Sustainable IPM through Host Plant
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Biological Control of Whiteflies by
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Progress of Cassava Mosaic Disease
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Management of the Cassava Mosaic Di
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Conclusions Conclusions The Tropica
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Conclusions whitefly pests and thus
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Conclusions developing countries, a
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Acronyms and Abbreviations Acronyms
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Acronyms and Abbreviations FIRA Fid
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Acronyms and Abbreviations PROFRIJO
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Acronyms and Abbreviations PYR pyre
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