EFFECTS OF LARVAL AGE ON SUSCEPTIBILITY OF COTTON LEAFWORM, Spodoptera littoralis (boisd.) (LEPIDOPTERA: NOCTUIDAE) TO Bacillus thuringiensis var. kurstaki | ||
| Journal of Plant Protection and Pathology | ||
| Article 2, Volume 29, Issue 10, October 2004, Pages 5855-5861 PDF (1.92 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jppp.2004.240016 | ||
| Author | ||
| M. D. Betana, | ||
| Central Agricultural Pesticides Laoratory, Agricultural Research Center, Dokki-Giza, Egypt | ||
| Abstract | ||
| Susceptibility of different instars larvae of cotton leafworm, Spodoptera Iittoralis (Boisd.) (Lepidoptera: Noctuidae) to Bacillus thuringiensis var. kurstaki was determined in the laboratory using a leaf dip bioassay. The concentration-mortality was used to estimate the relative susceptibility among the instars of S. littoralis. The results showed that there was no trend between successive instars, the second and fourth instars was the most and the least sensitive, respectively, and the third instar larvae was the least sensitive at second day. A sublethal concentration of B. thuringiensis var. Kurstaki was studied, the study proved adversely effect on the surviving larvae. Treated second instars had significantly weight less than the controls. Additionally, the pupal weight and adult emergence were significantly reduced. Moreover, reproductive potential and adult sex ratio of survivors was affected. Second instars of S. littoralis may be the main target to B. thuringiensis var. Kurstaki control. | ||
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