Inhibited reproductive capacity of Egyptian cotton leaf worm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) by the chitin synthesis inhibitor Novaluron.

Document Type : Original Article

Authors

Faculty of Science, Al-Azhar University, Cairo, Egypt

Abstract

For evaluating the effects of Novaluron on various parameters of the reproductive capacity of Spodoptera littoralis, a concentration range of 1.00-0.0001ppm was applied on the newly moulted penultimate (5th) instar larvae and a concentration range of 0.10-0.0001ppm was applied on the newly moulted last instar larvae.  A predominant inhibitory effect of Novaluron was exhibited on the oviposition efficiency since the oviposition rate was seriously regressed in no certain trend, regardless the time of larval treatment and concentration level. Treatment of penultimate or last instar larvae with Novaluron resulted in drastically reduced fecundity in a dose-dependent course. A reducing action of Novaluron was exerted also on fertility after treatment of larvae with different concentration levels, regardless the time of treatment. After treatment of penultimate or last instar larvae with Novaluron, the embryonic development had been generally subjected to a retarding effect since the incubation period was pronouncedly prolonged, regardless the concentration level.

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