Effect of gamma radiation on the protective efficacy of essential oil on stored cowpea against and .

Purpose: Cowpea is an essential pulse food in several regions throughout the world. Essential oil isolated from unripe fruits exposed to gamma radiation at dose levels of 0, 1, 3 and 5 kGy was evaluated as cowpea seed protectant against and .

Materials And Methods: Cowpea seeds were treated with three rates of the oils from non-irradiated and irradiated fruits, 0.5, 1.5 and 3.0 g kg. Mortality of and adults after 3 and 7 days, progeny reduction and weight loss of cowpea seeds after 45 days were recorded for all treatments.

Results: The pronounced mortality of adults was achieved at the highest rate 3.0 g kg of the irradiated oil with 5 kGy (98.3%). While in the case , all tested application rates induced marked adult mortality and a complete mortality (100%) resulted at two application rates (0.5 and 1.5 g kg) of irradiated oil with 5 kGy and 3.0 g kg after 7 days. Strong progeny suppression of and was resulted at the highest rate of 3.0 g kg of irradiated oil with 5 kGy (11.3 ± 0.3) and (8.5 ± 3.8) after 45 days of treatment, respectively. High protection of cowpea seeds with weight loss 0.5 and 1.4% for and was achieved at 3.0 g kg of irradiated oil dose of 5 kGy, respectively after 45 days.

Conclusions: Our results indicate that gamma irradiation of fruits improve the protective activity of their essential oil against and on stored cowpea seeds and the irradiated oil could be successfully used for management of these bruchid insects.