Potential of jatropha curcas seedcake as source of renewable insecticide and biofertilizer for two food crops legumes: a case study of peanut and bambara groundnut

The study was carried out in the field, in the southwest of Chad during the 2018 agricultural campaign. The objective of this work was to evaluate the biocidal and fertilizing effects of residues resulting from the extraction of Jatropha curcas oil on the control of pests of legume pods in the field. The experimental device was a split plot (2x4) with two factors: the first factor is the legume species (Vigna subterranea and Arachis hypogeae) and the second the treatments (J. curcasseedcake, J. curcas seedpowder, urea or positive control and control or negative control). The tests were repeated four times. Data on growth parameters, legume production and soil characteristics were collected. The results obtained indicated that the treatments had a significant effect (P <0.05) on the growth, development, dry biomass and seed yield of the plants. They have made it possible to raise the level of soil fertility to make it more profitable for agricultural activities. The insecticidal and insect repellant potential contained in the seeds of J. curcas helped to limit the damage caused by centipedes on peanut and bambara groundnut pods. This agricultural practice helps to widen the way for the practice and promotion of organic farming.