Insecticidal effects of Cassia tora and Cassia alata against cowpea weevil (Callosobruchus maculatus)

Abstract

A study on the effects of Cassia tora and Cassia alata against cowpea weevil (Callosobruchus maculatus) was conducted from April to July, 2016 and aimed at evaluating the effects of Cassia tora and Cassia alata in the control of cowpea weevil (Callosobruchus maculatus). The percentage mortality of Callosobruchus maculatus in white variety seeds of cowpea treated with concentrations 2g, 3g, 4g and 5g powder of Cassia alata are 40%, 50%, 70% and 90% respectively and Cassia tora of the same concentrations gave mortality percentage of 30%, 40%, 60% and 70% respectively. The mortality of adult C. maculatus was higher in both varieties treated with powdered mixture of both plant materials in ratio of Ca80%:Ct20% showed (90%) mortality followed by Ca50%:Ct50% with 80%. C. maculatus mortality according to variety was higher in the white variety than the brown variety with Ca20%:Ct80% mixture as (3.00±1.00) and (2.50±0.50) respectively. The weevil perforation index (WPI), increase as the concentration of the plant increased with Cassia alata having the highest weevil perforation index when compared to Cassia tora. There was significant difference (P<0.05) between combination of the two plants (Cassia alata and Cassia tora) and weevil perforation index for both varieties of cowpea seeds. Since the plant species showed efficacy and are cheap and readily available, it therefore be recommended, that the leaf powders of these two plants can be used in the control of adult C. maculates in storage of cowpea.