No abstract

Although Egyptian cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) is native in Africa, it is distributed throughout the world. It is a serious polyphagous insect damaging more than 90 host plants of economic importance. The objective of the current study was to evaluate the disruptive impact of Nerolidol, a Sesquiterpene compound, on the most important parameters of adult performance and reproductive potential of this insect. The newly moulted larvae of 5 th (penultimate) or 6 th (last) instar larvae fed castor bean leaves previously treated with 7 concentrations of Nerolidol (400, 200, 100, 50, 25, 12.5 & 6.25 ppm) for 24 hr. The most important results could be summarized as follows. Nerolidol exhibited an adulticidal activity only at the higher concentrations. Nerolidol exerted an anti-morphogenic activity against adult moths since some malformed adults were produced at the higher concentrations. Regardless the treated larval instar, Nerolidol induced the successfully emerged adults to live remarkably shortened total longevity and oviposition period, but the pre-oviposition period was generally prolonged. Nerolidol exhibited an inhibitory effect on the oviposition efficiency since the oviposition rate was deleteriously regressed, in a dose-dependent course. Nerolidol caused a disturbance of the reproductive capacity since fecundity and fertility were dramatically prohibited. After larval treatment with Nerolidol, the successfully mated adult females laid eggs with a significantly prolonged incubation period, especially at the higher concentration levels.

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

The Egyptian cotton leafworm Spodoptera littoralis (Boisduval) is a dangerous pest of many field crops and vegetables in the world. The present study was conducted to investigate the disturbing effects of the sesquiterpene compounds, Farnesol, Nerolidol, and Bisabolol, on the main body metabolites in larvae and pupae of this insect. The newly moulted last (6 th ) instar larvae were treated with LC 50 values of these compounds (33.67, 42.24 and 59.31 ppm, respectively) and the determination of the main metabolites was achieved in haemolymph and fat bodies of larvae and the homogenate of pupae. The most important results could be summarized as follows. The present study recorded predominant reducing effects of these compounds on the protein content in larvae and pupae with an exceptional enhancing effect of some compounds at certain ages of last instar larvae. Also, the lipid content in haemolymph and fat bodies of larvae as well as in the pupae was remarkably reduced. In addition, all compounds exhibited predominant reducing effects on the carbohydrate content in haemolymph and fat bodies of larvae and in the pupae, with two exceptions of increasing carbohydrate content in larval haemolymph (at 24 hr post-treatment) and in larval fat bodies by Nerolidol (at 72 hr post-treatment).

http://eajbsa.journals.ekb.eg/ Assessment of the Inhibitory Impact of Novaluron, A Recent Insect Growth Regulator, on the Reproductive Potential of Spodoptera littoralis (Boisd.)(Lepidoptera: Noctuidae).