Effect of high temperature on two major stored product insects and the effect on germination of cowpea seeds (Vigna unguiculata L.)

Abstract

Background The importance of the control of stored product insects is highlighted with a loss of more than one billion dollars per year. The present study included one of the most important natural bioassay methods (the effect of high temperature) for controlling stored-product insects. Results In the current study, the range used for high temperature (45–80°C) influenced the criteria (% mortality of adults and immature stages, %hatchability, and % reduction): as well as the effect on % weight loss and % germination. The Complete mortality 100% of Callosobruchus maculatus was obtained with the treatment 55^oC/40 minutes, 60^oC/30 min, 65 ^oC/20 min, 70 ^oC/20 min., 75 ^oC/15 min and 80^oC/5 min. The Complete mortality 100% of Rhizopertha dominica was obtained with the treatment 55^oC/30 min, 60^oC/25 min, 65 ^oC/20 min, 70^oC/15 min, 75^oC/10 min and 80^oC/5 minutes. Furthermore, the temperature at 45^oC/30 minutes, 55 ^oC/20 min, 60 ^oC and 65^oC/15 min, 70^oC and 75 ^oC/10 min and 80^oC/5 min did not have any harmful effects on wheat grain and cowpea seed germination. All treatments were similar to the untreated control. Conclusions The application of temperature has no side effects on humans or on the environment. The best results were achieved with application of temperature at 45^oC/30 minutes, 55 ^oC/20 min, 60 ^oC and 65^oC/15 min, 70^oC and 75 ^oC/10 min and 80^oC/5 min without injurious effects on grain and seed germination.