Population growth and life table studies of five polyphagous stored grain pests on green gram

Background Polyphagous stored grain pests, such as Sitophilus oryzae , Callosobruchus chinensis , Sitotroga cerealella , Rhyzopertha dominica and Trogoderma granarium are expanding their host ranges. Therefore, life table studies of these pests were conducted on green gram, since they have shown potential to infest this legume. Results The metabolites present in green gram were profiled, which led to differences in population growth among the pests. The immature period was longest in R. dominica , followed by S. cerealella , T. granarium , S. oryzae and C. chinensis . In contrast, S. oryzae greatly outlived the other four in terms of adult longevity. Population parameters, such as potential fecundity, gross reproductive rate and net reproductive rate, were highest in S. oryzae , while population growth rate and population size of the 2nd generation were highest in R. dominica . Meanwhile, the intrinsic rate of increase and finite rate of increase were highest in C. chinensis . These parameters were observed to be lowest in either T. castaneum or S. cerealella . We found direct correlations between host metabolites and the growth of the pest population. Conclusion The susceptibility of the green gram cultivar was found to be decreasing in the order of S. oryzae > R. dominica > C. chinensis > S. cerealella > T. granarium . Hence, protection measures need to be taken against R. dominica , S. oryzae and C. chinensis during storage of green gram. However, none of the tested pests completely dominated the population parameters. These findings help in modifying host metabolite profiles to improve resistance to SGPs.