Lethal and Sublethal Effects of Spinosad and Bacillus thuringiensis aizawai on Reproductivity of Spodoptera littroralis (Boisd.) and Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae)

Leathal and sublethal effects of Spinosad and Bacillus thuringiensis aizawai (Btx) against 4th instar larvae of the cotton leafworm Spodoptera littoralis (Boisd.) and the 3rd instar larvae of the beet arnyworm Spodoptera exigua (Hubner) were determined under laboratory conditions. LC50 values of Spinosad and Btx after 48h of treatment were 38.86 ppm and 8.47x10(7) spore+crystal/ml for S. littoralis and 12.63 ppth and 0.53x10(6) spore+crystal/ml for S. exigua. Spinosad and Btx, at their sublethal concentrations significantly increased larval and pupal developmental periods of both pests. Spinosad treatment for both pests had no significant effect on the preovipositional or ovipositional periods, egg viability, fecundity, viabilty percentage and number of spermatophores. Btx treatment did not significantly affect all the biological parameters of S. littoralis but affected significantly the oviposition/ day. Btx treatment did not significantly affect the number of spermatophore and ovipositional period of S. exigua but affected significantly fecundity, preovipositional period, egg viablity and the longevity of adults.