Comparative Efficacy of Jatropha curcas L. Seed Powder for the Control of Callosobruchus subinnotatus (Pic) on Stored Bambaranut, Vigna subterranea (L.) Verdcourt

The study was to assess insecticidal effectiveness of Jatropha curcas L. seed powder on Callosobruchus subinnotatus (Pic) infesting stored bambaranut, Vigna subterranea (L.) Verdcourt. The experiment was laid out in a factorial design of 4×2 levels (seed powder at the rates of 0.0, 0.5. 1.0 and 1.5 g, with and without addition of the synthetic insecticide at 0.01 g/20 g bambaranut seed) and laid out in a completely randomized design, in three replicates. Results obtained showed lowest oviposition, progeny emergence and seed damage (5.33, 1.58 and 1.83, respectively) in bambaranut seeds admixed with 1.0 g of the seed. Although, statistically similar to all other treatments, it was significantly (P≤0.001) better than the control treatment in which 33.83 eggs were laid and 24.08 adults emerged from 22.92 emergence holes. In addition, at six (6) days after treatment, highest adult mortality rate (99.17%) similar to that (99.17%) obtained in the synthetic insecticide was also recorded in seeds treated with 1.0 g seed powder. However, all other treatments were also significantly better than the control, in which 72.50% of the introduced bruchids died. Comparatively, lowest rate of seed damage (6.68%) and lasting effect was also obtained with the addition 1.0 g seed powder. In conclusion, appreciable level of protection on bambaranut seeds was achieved using seed powder of J. curcas. Therefore, it is recommended that for effective management of C. subinnotatus infesting bambaranut, farmers could use 5 Kg seed powder on 100 Kg bambaranut seeds.