Efficacy of Plants Extract in the Control of Cowpea Weevils (Collosobranchus maculatus) in Storage at Gombe and Makurdi, Nigeria

Abstract

Callosobruchus maculatus, a major storage insect pest of cowpea, lays its eggs on the pods or sometimes on the seeds both in the field and in storage. The larva perforates the seeds and completes its life cycle there. It can cause loss, if not controlled in time. The objective of this project was to examine the effect of plants extracts (Neem seed powder, Moringa seed powder and Pepper seed powder) on cowpea weevils as an alternative for preserving cowpea at storage at Gombe and Makurdi. The experimental design for the study was Completely Randomized Design with three replications. Data collected included; number of perforated seeds, number of mortality, number of eggs, number of adult weevils, germination percentage and weight of cowpea before and after the experiment at 4 weeks and 8 weeks.  Significant difference (P<0.05) was recorded on cowpea variety and plant extracts were Sampea 11 (white cowpea) recorded low in number of perforated seeds, number of mortality, number of eggs, number of adult weevils and weight of cowpea before and after the experiment at 4 and 8 weeks after infestation with germination percentage high where Sampea 12 (brown cowpea) records higher in all the parameters considered except in germination percentage where it recorded low. On plant extracts, pepper seed powder recorded the lowest in number of perforated seeds, number of mortality, number of eggs, number of adult weevils, and weight of cowpea before and after the experiment at 4weeks and 8 weeks with germination percentage high, control on the other hand recorded the highest in all the parameter in consideration except in germination percentage. Hence, Sampea 11 (white cowpea) variety shows superiority over Sampea 12 (brown cowpea) variety in all the parameters under consideration. Pepper seed powder also shows superiority over the other plants extracts used; pepper powder with Sampea11 is therefore effective in the control of C. maculatus when compared with other plant extracts. On location, Gombe stored better using sampea11 (white cowpea) and pepper extracts. Therefore, the use of pepper seed powder by cowpea farmers for effective control of cowpea weevils in storage and should adopt Sampea 11 (white cowpea) variety since it has resistance to cowpea weevils during storage.