Comparison between Gamma Rays and Magnetic Flux Effects on Biological and Life Table Assays of Earias insulan (Boisd.) Eggs

Document Type : Original Article


Plant Protection Research Institute, Agriculture Research Center, Giza, Egypt


            Under laboratory conditions, the spiny bollworm, Earias insulana (Boisd.) egg stage was exposed to two gamma rays (50&500 Gy) and magnetic flux (20&180 mlt) for studying some aspects of the pest act in biological and life table assays as affected by the treatments used. The results showed that:
     Gamma rays dose of 500 Gy was the most efficacies on E. insulana egg compared with other treatments used. The aforementioned dose caused 19.3% egg hatchability and the larvae were completely dead at 1st or 2nd instar larvae of E. insulana. A dose of 50 Gy had a hatchability percentage (75%), but it caused the increasing larval mortality and completely pupal stage death. Meantime, magnetic flux of 180 mlt, followed by 20 mlt had many deleterious actions for biological and life table parameters in E. insulana treated as one day old egg, it caused the decreasing hatchability, larval & pupal weights, longevity, sex ratio and no. of egg/female; on the other hand, it caused larval and pupal mortalities increasing.
     Life table parameters of E. insulana treated as egg affected by magnetic flux treatments. Female progeny/female (Mx), survival rate (Lx), net reproductive rate (Ro), intrinsic rate of natural increase (rm) and finite rate of increase (erm) were decreased in both treatments. Meanwhile, generation time (T) and doubling time (DT) were increasing as affected by magnetic flux treatments as one-day old egg compared with untreated E. insulana eggs.
     So, gamma-ray doses (50&500 Gy) treatments were the most efficacy against E. insulana egg stage than magnetic flux treatments (20& 180 mlt); but the magnetic flux caused severe deleterious on E. insulana biological and life table parameters.