Evaluation of the Insecticidal Potential of Jatropha curcas Seed Extracts on Pests of Okra in the Field

Abstract

Okra (Abelmoschus esculentus) is one of the main plants of high nutritional importance cultivated in Cameroon. However, its production is compromised by many constraints including the presence of insect pests, which are responsible for losses in the farms. The present study was carried out on the campus of the University of Yaoundé I. Its objective was to evaluate the insecticidal potential of Jatropha curcas seed extracts on the insect pests of okra. Two varieties of okra (Clemson and Hire) were used. Five treatments (T0: control, T +: Lamida gold 90EC insecticide, T-EAQ: treatment with the aqueous extract of J. curcas seeds, T-EAC: treatment with acetone extract of J. curcas seeds, T-E EAE: treatment with ethyl acetate extract of J. curcas seeds) were used in a completely randomized block design with three repetitions. Growth parameters, the number of insects, severity of phyllophages and fruit yield were evaluated. The results showed that a treatment and varietal effect was observed statistically significant on all growth parameters. The pests identified were: Aphis gossypii, Cheilomenes sp, Dydercus spp., Nisotra spp., Podagrica spp., Zonocerus variegatus. Aqueous and organic extracts of Jatropha curcas seeds were effective as Lamida gold insecticide against phyllophages in compared to the control. The best yield was obtained in T-EAQ treatment (9945.45), followed by T+ (8917.31), T-EAE (6712.9) and T-EAC (6149.9) compared to control T0 (4791.3). Variety V2, although having a susceptibility to insect attack, presented the highest yield (7158.9 kg/ha) compared to (6503.78kg/ha) for V1. Aqueous and organic extracts of J. curcas seeds appear to be a promising avenue in the integrated control of okra pests. Therefore, they can be valorized.