A survey of the damage caused by the Callosobruchusmaculatus (F.) on different legume seeds sold in Njikoka Local Government Area, Anambra State, Nigeria

Abstract

Callsobruchus maculatus (F.) commonly called cowpea weevil is a major pest of stored leguminous seeds. The level of damage caused by C. maculatus (F.) on five different legumes on sale in Njikoka L.G.A., Anambra State was studied for a period of six weeks. The legume seeds were Vigna unguiculata var. brown (Brown cowpea) and Vigna unguiculata var. white (White cowpea), Glycine max (Soya beans), Vigna subterranea (Bambara nuts) and Cajanus cajan (Pigeon pea). They were purchased randomly from local traders at Orie-Agu market in Abagana, Anambra State. Clean seeds without infestation were selected for the study. One hundred grammes (100g) of each legume seeds were used. The weevils used for the study were reared in the laboratory. The F1 generation was used to infest the clean legume seeds. The weevils were introduced in different male to female ratios and containers covered with white muslin cloth to allow aeration. The experimental setup was left to stand on the laboratory bench while weight loss and emergence holes were observed at two week intervals for a period of six weeks. The treatments with the higher male to female ratios of weevils showed highest damage to legume seeds (15.08 ± 0.93). V. unguiculata-Cowpea (var. white) was the highest damaged seeds (13.88 ± 1.00), while G. max-soya beans were least damaged (2.24 ± 1.36). The damage done by the weevils on the different legume seeds were statistically significant (P<0.05) using Analysis of Variance (ANOVA) and Post Hoc tests. Damaged seeds could lead to serious economic losses for both the farmers and the country. Early harvest, good storage practices and facilities to reduce the attack of these pests on legume seeds is recommended.