First steps to improve cotton crop management in Thailand.
Thai cotton growers yearly face serious pest problems consisting of heavy infestation associated with resistance to pesticides leading to expensive and harmful pest control practices. Thanks to a multi discipline research work carried out from 1991 to 1996, a decision-oriented model for cotton crop management was developed and compared to farmers' practices during the 1988 cotton growing season 1998 in Klang Hat district, Thailand. This model, based on plant monitoring, involved a new cotton cultivar (DORA 11 as a replacement for Sri Samrong 60), seed treatment with imidacloprid (at 3.5 g of a.i./kg of seeds), a threshold-based spray of mepiquat chloride, a cotton growth regulator (Pix at 1.5 l/ha) and a set of rules to selectively control with chemical and biological insecticides the major pests the American bollworm (Helicoverpa armigera Hübner) and the cotton leafhopper (Amrasca biguttula biguttula Ishida). This package was more friendly towards environment than farmers' practices since seed treatment does not harm beneficials at the beginning of cotton growing season while 1 and 5 sprays were saved against respectively the American bollworm and sucking pests and more than 50% of the sprays directed against American bollworms involved biological insecticides (Bacillus thuringiensis toxins potentialized by a low dosage of endosulfan). Threshold-based sprays against the main pests, the use of a cotton growth regulator, earliness of cotton cultivar and seed treatment were accountable for savings in pesticide sprays. Involving a biological insecticide and endosulfan at the beginning of cotton growing season and using the same quantity of active ingredient at each spray during the cotton growing season also improved the management of pyrethroid resistance in American bollworm populations was also. There was no significant difference between yields inside farmers' fields and innovation plots. However, thanks to cheaper pest control practices economic results were better. Lastly few improvements of this package are proposed.
Renou
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CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement) programme coton TA 72/09 Avenue Agropolis Boulevard de la Lironde, 34 398 Montpellier. alain.renou@cirad.fr
Pagès
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Dessauw
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Charusri
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D000383:Agriculture / Q000191:economics / Q000379:methods*; D000818:Animals; D001413:Bacillus thuringiensis / Q000502:physiology; D004726:Endosulfan; D004731:Endotoxins; D003368:Gossypium / Q000469:parasitology*; D007300:Insect Control / Q000379:methods*; D007305:Insecticide Resistance; D007306:Insecticides; D010572:Pest Control, Biological / Q000191:economics / Q000379:methods*; D012621:Seasons; D012639:Seeds; D013785:Thailand
D004731:Endotoxins; D007306:Insecticides; D004726:Endosulfan