Damage Potential Between South Indian Bruchid Strains of Callosobruchus maculatus and Callosobruchus chinensis

Pulses serve as an important food component in many developing countries including India. Due to high protein content, these crops are constantly faced with different abiotic and biotic stresses such as drought, insects and diseases which ultimately lead to decreased productivity. Among the biotic stresses, seed beetles in the genus Callosobruchus constitute a major constraint in pulse production causing high grain losses both in quantity and quality during storage, and are distributed all over the country. In this context, an experiment was conducted to assess the seed damaging potential of two most common Callosobruchus species, Callosobruchus chinensis and C. maculatus, on an important Indian pulse crop, mung bean (variety - CO-8) through artificial infestation under laboratory conditions. Results showed that ovipositional response by the two species differed significantly on 50 mung bean (Vigna radiata) seeds. Damage potential of the two bruchid species was evaluated by assessing and comparing seed damage percentage. Seed infestation was significantly higher for C. maculatus (91.33 %) than C. chinensis (70.67 %). Although mung bean seeds were highly susceptible to both the bruchid species, however, mean developmental period (MDP in days) was found to be significantly different which recorded 29.96 and 24.99 days for C. chinensis and C. maculatus respectively. Therefore, it can be concluded that C. maculatus is more dominant and damaging than C. chinensis and hence, can be recommended for use in bruchid host plant resistance study.