Influence of Morphological Attributes of Cowpea Genotypes on Oviposition of Pulse Beetle (Callasobruchus maculatus F.)

Abstract

Background: Cowpea is an excellent host for Callasobruchus maculatus (F.). These beetles cause havoc in stored cowpea. They have the habit of cementing their eggs to the surface of the host seeds. Hence, the present study was aimed to the find the influence of morphological characters of cowpea varieties/genotypes on oviposition of the pulse beetle. Methods: The ovipositional preference of C. maculatus on 14 cowpea varieties/genotypes was studied under the free choice condition and the data thus obtained were correlated with the morphological characters like seed shape, colour and texture. Result: Each variety/genotype had a significant effect on egg laying by C. maculatus. Significantly least oviposition was noticed in GC 3 (35.33 eggs), having a rough testa texture and greater number of eggs were found on GC 1612 (117.33 eggs) having smooth texture. The pulse beetle preferred smooth textured seeds for egg laying irrespective of its shape and colour. This was again confirmed by one of the genotypes GC 1702, which belongs to the Holstein group based on the eye pattern of the cowpea, in this genotype the pulse beetle preferred to lay eggs on the smooth brown portion surrounding the hilum than the wrinkled white portion.