Potentials of Three Plants Leave oils mixture in Protecting Maize Grains against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Over the last decade, Sitophilus zeamais are being control using synthetic insecticides. The over- use of these chemicals has lead to the development of insecticides resistance, environmental pollution, and killing of non-target organisms. The efficacy of Hyptis suaveolens, Ocimum gratissimum, and Psidium guajava leaf oils combination against adult S. zeamais was investigated on maize grain during the study. The leaves of the plants were grounded into powders and oils were extracted using Soxhlet apparatus separately. Maize variety 99% EDVT used was obtained from the International Institute for Tropical Agriculture (IITA) Kano. The insects were cultured in a containers and identified using a standard taxonomic key for Sitophilus spp. Different oils combination of two plants leaves oils were made in the ratio of 50%:50% of the test dose 0.1, 0.2, 0.3, and 0.4ml/20g.Ten newly emerged S. zeamais were introduced separately for examination of adult mortality test and lethal concentration determination. Results showed that mortality increases with exposure period. The leaves oils combination show a significant difference in adult mortality of S. zeamais (P<0.05). Isobutylcyclohexane, Oleic Acid and 11-octadecenoic acid were the most occurring compound present in the individual plant extract. H. suaveolens and O. gratissimum combination protecting maize grains against S. zeamais infestation and therefore, the active ingredient of these plant combinations should be evaluated.