The effect of pesticides and aqueous extracts of Azadirachta indica (A. Juss) and Jatropha carcus L. on Bemisia tabaci (Gennadius) (Homoptera: Aleyrididae) and Helicoverpa armigera (Hübner)(Lepidoptera: Noctuidae) found on tomato plants in Côte d’Ivoire.

Abstract

Objective : The objective was to evaluate the effects of foliar application of Jatropha and neem aqueous extracts compared to a conventional insecticide treatment on the number of whitefly Bemisia tabaci ( Gennadius) and bollworm Helicoverpa armigera (Hubner), yield of tomatoes in plots and the potentials of using any of these aqueous extracts to control these insect pests. Methodology and results: the study was conducted in the region of Moronou (Bongouanou, Koffikro, CBC Kangandissou). The insecticides Decis 12 EC® and Cypercal 50 EC®, and neem and jatropha aqueous extract were used for tomato foliar treatment (neem and jatropha seeds 80 and 50g/L, neem leaves 67 g/L). The treatments of tomato plant plots with pesticides Decis® and Cypercal® showed similar yields of biopestcide made of neem and jatropha in Ahorosso (P=0.00), Bongouanou (P=0.07) and CBC Kangandissou (P=0.01) plots. All of these treatments reduced the number of Bemisia tabaci adults, reduced the number of Helicoverpa armigera larvae on tomato plants and increased number of fruits per plant, the fruit weight per plant and the yield. Conclusion and application of findings : Statistical analysis shows that aqueous extract of jatropha and neem seed 80 g/L and 50 g/L, and of neem leaves 67 g/L are as effective as pesticides Decis® and Cypercal® on Bemisia tabaci and Helicoverpa armigera. Consequently, these biopesticides increased the number of fruits per plant and yield. This result should enable use of aqueous extract of neem and jatropha seed and of neem leaves to protect tomato plants against Bemisia tabaci and Helicoverpa armigera at farm. Keywords : Bemisia tabaci; Helicoverpa armigera ; tomato crop; aqueous extract; biocontrol