COMPARATIVE STUDY OF CERTAIN INSECTICIDES AND THE MIXTURES OF SOME PLANT OILS AGAINST COTTON LEAFWORM Spodoptera littoralis (BOISD)

Authors

1 Inst. Plant Prot. Res., Cent. Agric. Res., Egypt.

2 Dept. Plant Prod., Fac. Environ. Agric. Sci., Arish Univ., Egypt.

Abstract

Laboratory experiments were conducted under controlled conditions to test the insecticidal activity of two insecticides i.e. Cypermethrin (25% E.C) a synthetic pyrethroid and Chlorpyrifos (48% E.C) an organophosphate insecticide. Also five plant oils were used in a ratio (1:1) i.e (v/v) and they were as in following: Menth piperita L., Syzygium aromaticum L., Cinnamomum camphora L., Allium sativum L. and Anethum graveolens L. The 4th instar larvae was used in bioassay of these insecticides and oils alone and the mixture of (insecticide: oil). The acute toxicity (LC50) of each treatment recorded after 120 hr. Also the toxicity index (T.I) and relative potency (R.P) were calculated. The results showed that cypermethrin is more toxic than chlorpyrifos, also the Allium sativum L. was the most toxic oil and the lowest one was oil Syzygium aromaticum L. Finally the most toxic mixture was with cypermethrin, especially the mixture of cypermethrin and Allium sativum L. (1:1).

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