Oviposition behaviour of Callosobruchus chinensis (L.) (Coleoptera, Chrysomelidae, Bruchinae) on horse gram seed varieties

Oviposition behaviour of Callosobruchus chinensis was tested on six varieties of horse gram seeds (ANK Black, AK 42, AK 21, BK 1, Urmi and Paiyur 1) to identify the resistance variety. In no choice test, females of C. chinensis laid lesser eggs within 24 h of mating on whole seeds of Urmi variety (11.6 ± 0.41) than the other varieties tested. However, females did not lay eggs when seed coat was removed from the above six varieties of horse gram. In choice test, females laid the lowest number of eggs within 24 h of mating on Urmi (1.11 ± 0.23) than the other varieties. The scanning electron micrograph (SEM) study revealed that there were morphological differences on the seed coat texture of the six horse gram varieties. The seed coat texture of Urmi variety is heterobrochate with some nearly bi-reticulate patches and few unevenly depressed muri, which partially inhibited oviposition on Urmi seeds. Urmi is the less preferred variety for oviposition.