Laboratory Investigation on Oviposition and Development of Callosobruchus maculatus (F.) on Four Varieties of Cowpea
Cowpea, one of the six major cultivated crop species of the family leguminosae distributed throughout the tropics is a cheap source of protein. It has about 20-25% protein content, containing about twice the protein content of most cereals and it is also rich in vitamins, minerals and low in fats. Even though cowpea is nutritionally important to many people, its cultivation is under treat from insect pests both in the field and storage but the most damaging pest of cowpea in storage is Callosobruchus maculatus. The oviposition, growth and development of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) on four (two resistant and two susceptible) varieties of cowpea were investigated under laboratory conditions in the Department of Crop Protection, University of Ilorin. This was done to ascertain the resistance of the selected cowpea varieties to attack by C. maculatus. The experiment was laid out in a completely randomized design with five treatments namely Ife-brown, TVU-2027, Vita-7 and IT86D-535. Each treatment was replicated three times More eggs were laid on Ife Brown when compared with TVU 2027. However, fewer eggs were laid on Vita-7 when compared with IT86D 535. C. maculatus developed best on the seeds of Ife brown followed by IT86D 535 and Vita 7. Few adult insects emerged from TVU 2027. Developmental period was longer in TVU 2027 than in Ife brown, IT86D 535 and Vita 7. The largest number of adult males and females were reared from Ife brown.
Keywords: Cowpea varieties, Callosobruchus maculatus, oviposition and