Callosobruchus chinensis (Coleoptera: Chrysomelidae): Biology, life table parameters, host preferences, and evaluation of green gram germplasm for resistance

Abstract Pulse beetle (Coleoptera: Chrysomelidae) is a notable insect pest of green grams, garden peas, chickpeas, cowpeas, lentils, black grams, and pigeon peas. Callosobruchus chinensis L. can cause huge quantitative and qualitative losses and also decrease the nutritional values of stored grains/pulses. The biology, life table parameters, and host preference of C. chinensis were studied in three pulses - green grams, lentils, and cowpeas. We also evaluated the green gram germplasms for resistance to C. chinensis. Cowpea was the most appropriate host for the culturing of C. chinensis under laboratory conditions among the three pulses. C. chinensis exhibited higher fecundity, shorter development period, and longer female longevity in cowpeas than green grams and lentils. The relative growth rate of C. chinensis was 0.101 ± 0.006 mg/day. The finite growth rate, intrinsic rate of increase, and net reproduction rate demonstrated a faster increase in the C. chinensis population in cowpeas than green grams and lentils. We observed the overlapping patterns in the life expectancy, survival rate, and reproductive results of C. chinensis on cowpea, green gram, and lentil; this universal pattern is important in assessing the life table parameters. Based on growth index, we graded 20 green gram germplasms as resistant (6), moderately resistant (7), moderately susceptible (2), susceptible (3), and highly susceptible (2). The green gram germplasms resistant to C. chinensis, EC920900, IC616111, IC616247, IC616161, IC616258, and IC616138 have the potential in reducing the loss of green grams during storage. To summarize, cowpeas can be utilized for continuous mass rearing of C. chinensis in the laboratory and the resistant germplasms can be used as donor in future breeding programmes.