Joint action between some vegetable oils and their methylated form against the 4th larval instar of Spodoptera littoralis (Boisd.)

Document Type : Original Article

Authors

1 Dept. of Econ. Entomol. & Pesticides, Fac. of Agric. Cairo Univ., Giza, Egypt

2 Pesticides Central Agric., Pesticides Laboratory, Agric. Res. Center, Dokki, Cairo, Egypt

10.21608/jpces.2006.460725

Abstract

The toxicity and the joint action of some vegetable oils and their methylated products were evaluated in laboratory studies against the 4th instar larvae of Spodoptera littoralis. Thin film technique was used as a method of application in this investigation. Cumin oil was the most effective at the LC50, level whereas nigella oil was the least toxic one. Their LC50 values were 0.08 and 0.2 µl / cm2, respectively. The other four oils, garlic, caraway, thyme and castor bean had LC50 values ranged from 0.12 to 0.16 µl / cm2. The methylation of the tested oils appeared change in the efficiency, either decrease or increase against 4th larval instar. The methylation process increased the efficacy of two oils (garlic and nigella) while decreased it, in another two oils (caraway and cumin) at LC50 and LC90 level. On the other hand, the methylation of castor bean oil decreased the LC90 value from 0.79 to 0.66 µl / cm2, while its LC50 value increased from 0.16 to 0.34 µl / cm2. Three experiments were conducted to study the joint action of the binary mixtures of vegetable oils and methylated vegetable oils against 4th larval instar. The first experiment was mixing LC25 of two vegetable oils together, the second one was mixing a vegetable oil with a methylated one and the third one was mixing the methylated oil with other methylated one. Results indicate that out of 49 tested mixtures; only 38 pairs showed potentiation, 7 pairs produced additive effect and 4 pairs disclosed antagonistic effect.

Keywords

Journal of Pest Control and Environmental Sciences
Volume 14, Issue 2
December 2006
Pages 91-105

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