Effect of the seed oil of three Botanicals, Jatropha curcas (L), Helianthus annus (L) and Cocos nucifera (L) on the maize weevil, Sitophilus zeamais (Mots)

The insecticidal properties of seed oil of three botanicals namely Jatropha curcas, Heliathus annus (sunflower) and Cocos nucifera (coconut) were tested on the maize weevil, Sitophilus zeamais Mots. The application doses were 0.1ml, 0.2ml, 0.3ml and 0.4ml per insect. There were a total of 20 insects per Petri-dish. Mortality was monitored daily for three days. The results of insects treated with all dosage rates of Cocos nucifera showed a significantly higher mortality when compared with the control. The least mortality being 50% for the least dosage applied after 24hours. In the case of H. annus, insect mortality ranged from 40%-100%, 70%-100%, 60%-100% and 80%-100% for rates of 0.1ml, 0.2ml, 0.3ml and 0.4ml respectively from 12hours to 24hours post application. The least rate of application of Jatropha produced 70% mortality after 24hours, while the dosage of 0.3ml and 0.4ml produced 80% mortality after 24hours. The control experiment remained at 0% level throughout the period of the experiments.Key Words: Seed oil, Botanicals insecticide, Sitophilus zeamais