Effect of ultraviolet radiation UV at eggs and larvae of the lesser grain borer beetle Rhyzopertha dominica (Fab.) (Coleoptera: Bostrichidae).


The effect of ultraviolet radiation UV on the eggs and larvae of the lesser grain borer beetle Rhyzopertha dominica (Fab.). It is used in this study length wave 312 nm of ultraviolet radiation(UV) and with different periods times (10,15,20 minutes). The results are showed the following : The eggs very sensitive and two periods age (1-2),(5-6) days increased whereas mortality with increasing of periods exposed to UV radiation in comparison with controlling and the eggs were the age (1-2) days that will be more sensitive towards UV radiation from eggs(5-6) days in all periods exposed , and mortality are 55.86 , 45.35 % for tow ages (1-2), (5-6) days respectively when exposed for period 20 minutes and increased the mortality larvae and pupae which are resulted from that eggs treatment . In concerning larvae for the two periods 2nd and 4th stage to UV radiation exposed .The sensitivity of 2nd larvae was higher than 4th stage in the all exposed periods (15,20,25) minutes. Mortality was highest and it results 54.78 , 37.42 % for 2nd and 4th larvae stage respectively in 25 minutes exposed . The study showed increasing of pupae deformations which resulted from 2nd and 4th larvae treatment. As results showed decreasing ratio emergence adults with different stage and period of exposing to larvae . We found the ratio emergence adults to 2nd larvae stage treatment are less than concerning to 4th larvae stage in all treatment they were the least which are 13.30 % for 2nd stage larvae in period 25 minutes exposed .