Insecticidal effects of azadirachtin on the cotton leafworm, Spodoptera littoralis (Boisd)

Document Type : Original Article

Authors

1 king Saud University, College of Agriculture, Plant Protection Department, Riyadh 1 1451 P. O. Pox 2460

2 King Saud University, College of Science, Zoology Department. Riyadh 11451 P. O. Pox 2455

10.21608/jpces.2003.459429

Abstract

The effects of Neemix 4.5 % (4.5 % azadirachtin) on different larval instars of the cotton leafworm, Spodoptera littoralis, were studied by feeding the larvae on castor bean leaves treated with different concentrations of azadirachtin. The second instar larvae were the most sensitive amongst the three larval instars exposed to various treatments. The concentrations that caused 50 % reduction in pupation of the second, third and fourth larval instars were 3.67, 10.75 and 10.92 ppm, respectively. Azadirachtin caused different effects including stop of feeding, inhibition of pupation, formation of intermediates and malformed pupae and adults. The compound showed contact toxicity when it was applied topically to the larvae and contact toxicity much less the feeding toxicity. Topical application treatment caused same effects of feeding toxicity. The treatments caused reduction of egg mass production in a concentration-dependent manner. However, azadirachtin did not prevent S. littoralis females from oviposition on treated plant leaves. The results generally indicate that azadirachtin is a successful insecticide, which may be used in integrated pest management programs to prevent or delay appearance of resistance to conventional pesticides

Keywords

Journal of Pest Control and Environmental Sciences
Volume 11, Issue 1
June 2003
Pages 77-86

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