Biocidal effects of jatropha curcas oil on the main insect pests associated with cowpea (vigna unguiculata) crops in soudanian savannah of chad

This study was carried out with the objective to evaluate the insecticidal effects of Jatropha curcas oil on three devastating insects of cowpea.A device in randomized complete blocks comprising 6 treatments and 4 repetitions was set up in field.The compound biocide of J. curcas oil used was an emulsifying formulation stabilized by ethanol and arabic gum.The spraying was carried out three times : at the start of the formation of flower buds corresponding to 35 Days After Sowing (35 DAS); at 50% flowering (45DAS) and early pod formation (65DAS).The biocidal effects of Jatropha oil has reduced damage with an effectiveness from 80 to 100% on aphids, thrips and bugs, the main cowpea pests in fields. It caused a highly significant (p˂0,001) increase in seed yields (kg.ha-1) compared to negative control.The yields obtained are 883,72±2,32 ; 1187,81±2,26 ; 1117,81±3,12 and 1109,82±4,11, respectively for concentrations 5, 10, 15 and 20 ml of J. curcas oil for 100 mL of preparation compared to the negative control (698,31±2,45).Ultimately, it emerges from these results that the use of Jatropha oil as a bioinsecticide bodes better tomorrow for the cultivation of J. curcas and opens up prospects for for biological and sustainable agriculture.