Effect of IGIs and IGRs on Embryonic development stages of Agrotis ipsilon (Hufn.) (Lepidoptera: Noctuidae).

Histological study was conducted in order to add to the previous studies concerning studied the effect of LC₅₀ of pyriproxyfen and tebufenozide as insect growth inhibitors (I.G.Is) and hexaflumuron, flufenoxuron and lufenuron as insect growth regulators (I.G.Rs) on different ages of Agrotis ipsilon(Fam. Noctuidae)eggs. The effect of LC₅₀ for these compounds were studied on the embryonic development. The treated deposited eggs showed acute effect causing decomposition to yolk content and defects in early stages such as germ band. In advanced stage after treatment, the embryonic development may be stopped and defective embryos were found. Histological examination of pyriproxyfen treated A. ipsilon eggs early showed various effects of treatment on the embryonic development such as a clear shortening of the formed germ band and great blockage of the embryonic development at the gastrulation stage. Eggs treated with tebufenozide, the embryonic development was inhibited showing the formation of undifferentiated of tissues and showed a clear invagination in the germ band. Application of flufenoxuron caused separation of the embryo components and the eggs became without strong chorion. Hexaflumuron caused undifferentiation tissues was apparent. On the other hand, the weakest effect was found when lufenuron was used at 24- 48 hrs. old of A. ipsilon eggs where a slight inhibition of embryonic development was occurred.