Participatory evaluation of synthetic and botanical pesticide mixtures for cotton bollworm control

Abstract

Abstract. The bioefficacy of various plant extracts, namely Azadirachta indica A. Juss, Khaya senegalensis Desrousseaux (A. Jussieu) and Hyptis suavuolens (L.) Poit, either alone or in combination with half the recommended dose of synthetic pesticides, was studied with farmers to find a more sustainable strategy for the management of bollworms in cotton. A number of treatments were farmer innovations. The treatments were compared six times during the season to the application of the fully recommended dose of synthetic pesticides and to a control with no pesticide application. Applications of either the fully recommended dose of the synthetic pesticides or the combinations with a neem seed extract (6 kg/ha) were most effective in reducing bollworm incidence and damage. Both the treatments gave the highest yields of cottonseed, the latter being the most costeffective. All the pesticides used, except neem alone, had a toxic effect on bollworm predators. This study has increased farmers' confidence in endogenous technology. The researcher's interaction among the local learning group members, who conducted the experiments, facilitated the introduction of a cost-effective alternative to the standard fulldose synthetic pesticide recommendation.Key words: cotton, plant extracts, synthetic pesticides, bollworms, endogenous technology Résumé. Dans le but de trouver une méthode de lutte durable contre les chenilles ravageuses du cotonnier, I'efficacité biologique de différents extraits de plantes (Azadirachta indica, Kaya senegalensis et Hyptis suavolens) a été évaluée, en milieu paysan, seule ou en association avec des demi-doses d'insecticides de synthèse. Certains des traitements sont le résultat d'innovations paysannes. Les traitements ont été comparés six fois au cours de la saison culturale à des applications normales d'insecticides ou la combinaison de synthèse et á des traitements témoins. Les traitements, avec des doses normales d'insecticides ou la combinaison de I'extrait de graine de neem (6 kg/ha) associé à une demi-dose d'insecticides de sysynthèse, ont été les plus efficaces pour réduire la densité des chenilles et leurs dégâts. Ces deux traitements ont donné les meilleurs rendements avec un ratio coû t/bénéfice plus avantageux pour la mixture insecticide de synthése-exrait de graine de neem. Tous les insecticides utilisés à I'exception de I'extrait de neem utilisé seul, ont eu un effet toxique sur les prédateurs des ravageurs du cotonnier. Cette étude accroît la confiance des fermiers dans les locales. L'interaction entre le *

Screening for antifeedant and larvicidal activity of plant extracts against Helicoverpa armigera (Hübner), Sylepta derogata (F.) and Anopheles stephensi (Liston)

“…Earlier authors reported that neem seed extract (6 kg/ha) were most effective in reducing bollworm incidence and damage, and produced the highest yields of cottonseed (Sinzogan et al 2006). The aqueous seed extracts of Azadirachta indica were applied at the rate of 30, 50, 75 and 100 g/l to control S. derogata and reported high fruit yield of okra plant in Ghana (Obeng-Ofori 2003).…”

Botanical insecticides: for richer, for poorer

“…Juss., pignut = Hyptis suaveolens (L.) Poit.] provided greater efficacy than the conventional products alone at their recommended rate 10. None of the plant extracts alone provided adequate crop protection.…”

Pathogenic Responses of Cowpea (<i>Vigna unguiculata</i>) Inoculated with Cucumber Mosaic Virus to Soil Amendment with Neem Leaf Powder

“…In a study of damage to cotton by the bollworm (Helicoverpa armigera H¨ubner) in Benin, it was reported that mixtures of extracts of three local plants Azadirachta indica, Khaya senegalensis, Hyptis suaveolens provided greater efficacy than the conventional inorganic products at their recommended rate (Sinzogan et al,2006). The incidence and severity of virus diseases is considered to be directly related with availability and abundance of insect vector and depend upon the time of infection (Dhingra and Ghosh, 1993).…”