Sterilizing Activity of the Insect Growth Regulator, Lufenuron on Drosohpila melanogaster (Meigen)

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Due to the complicated problems coming from excessive applications of insecticides, searching of safe substitutes to these insecticides has become necessity. Thus, the insect growth regulators are candidated to be used in such concern. The insect growth regulator, lufenuron was applied against Drosophila melanogaster (Meigen) as mixed with the diet of the larvae, with concentrations of 5, 10 and 20 ppm to test its efficacy as a sterilizer. Data showed that 5ppm treatment pushed up the larvae to speed pupation by the first two days after treatment. Overall results showed that 20 ppm recorded the highest pupation (94%) followed by 5, 10 ppm and control treatments with values of 87.5, 85.3 and 82.4%, respectively. The top concentration also caused the lowest adult emergence recording 39.4% then, 10, 5 ppm and control with values of 44.8, 71.4 and 85,7%, resp. The mortalities were arranged in descending order as follows 76.9, 35.0, 7.7 and 4.2% at 20, 5, 10 and control respectively. There were no dead adults recorded except on the ninth day at 10 ppm concentration and control. Regarding the sex ratio, it was greatly affected by lufenuron. It tended to increase the number of males. The number of males was four times the number of females at 5 ppm (1:4). There were no females at 20 ppm (0:12). Number of females was similar to that of males at 10 ppm (1:1). According to these results, the number of the output generation recorded 16 and 80 individuals after 10 and 15 days resp., compared to 96 and 220 individuals respectively in control. Females put eggs on the diet surface at 10 ppm, but it did not hatch. Uncompleted emergence was recorded at 5 and 20 ppm (21.4 and 52.9 %, respectively). Adults with deformed wings were recorded at 20 ppm as 11.8%. Total protein analysis and phenoloxidase activity were carried out. The reduction in total protein occurred in females due to lufenuron treatment. The highest reduction was 16.67 mg/ 1000 insects at 10 ppm concentration that affected on female fecundity. Phenoloxidase activity was high in males. It recorded 1153.33 M O.D./1000 insects at 10 ppm, which affected in male fertility. This may explain why the eggs did not hatch.