Microwave radiation as an Eco-friendly tool for controlling the red flour beetle tribolium castaneum (Hbst. )‎ (coleoptera : tenebrionidae)‎

Abstract EN

The current investigation aimed to assay a non-traditional method to control the red flour beetle Tribolium castaneum without any changes on contents and quality of wheat grains they infest.

Therefore, a household microwave system was used to assay the effect of microwave radiation on different developmental stages (larvae, male pupae, female pupae and unsexed adults) of the red flour beetle Tribolium castaneum (Hbst.), where all experiments were conducted at an exposure range of times of 3-20 s at power level of 800 W.

Meanwhile, the effect of microwave radiation on treated wheat grain characters and germination was also investigated.

The results showed that as the microwave exposure time increase, the mortality of different developmental stages of T.

castaneum increased.

The mortality of treated larvae of all ages (1-7, 7-14 and 14-21 days), male pupae, female pupae and adults were 100% at the power and exposure time of 800W and 20 s, respectively.

The median lethal time (LT50) of exposure to microwave irradiation indicated that the adult stage (LT50= 8.951±0.114 s) was more tolerant to microwave irradiation than pupae (LT50= 4.015±0.0.230 s).

The calculated percentage means of germination for the exposed grains to microwave radiation at 20, 15 and 10, decreased from 94.17% in the untreated control up to 40.83, 63.33 and 70.83 %, respectively.

High degradation and aggregation of DNA of the red flour adult beetle were detected after the microwave treatment of 400W for 20 s.

The results showed that there were 8 bands of esterases while the control pattern showed only 4 bands which prove that the adults increasing their enzymes activity as a way of protecting themselves from the produced radiation stress from the microwave.

It could be concluded that the microwave (800 W)-treated grains or flour for 20 s can be stored free of different developmental stages of the red flour beetle and can be used only for consumption purposes.

Because the germination of the treated grains was affected and rather reduced, while the composition of the grains (carbohydrates, fat, protein, ash, fiber and water content) was not significantly affected