Evaluation of Ripe and Unripe Pawpaw Seeds Powder in the Control of Callosobruchus maculatus in Stored Cowpea

Abstract

As alternative to the use of these synthetic insecticides, plant extracts, powders and ash have been used as cheaper and eco-friendly means of controlling C. maculatus infestation of stored cowpea seeds. This study was carried out to investigate the contact toxicity of ripe and unripe pawpaw seeds powder, both at concentration of 0.2g, 0.4g, 0.6g, 0.8g, and 1.0g per 20g of cowpea seeds. The plant powders were effective in controlling the population of C. maculatus at 48 hours of treatment across the treatment concentrations, the unripe pawpaw seeds powder were more effective at the treatment rate of 1.0g in the mortality rate. However, their effectiveness was dependent on dosage rate and period of application. The high mortality rate, reduction in the number of eggs laid, low adult emergence and low seed weight loss achieved by the effects of plant powders on the beetles was directly proportional to the increase in their application rates. The effective control of the activities of C. maculatus in seeds treated with ripe and unripe pawpaw seeds powder may have been due to their toxicity effects.