Signs on The Persistence And Effectiveness of Some Novel Insecticides Against Spodoptera littoralis (Boisduval) on Different Host Plants | ||
| Egyptian Academic Journal of Biological Sciences, F. Toxicology & Pest Control | ||
| Article 13, Volume 7, Issue 1, December 2015, Pages 105-113 PDF (341.75 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/eajbsf.2015.17245 | ||
| Author | ||
| El-Zahi S. El-Zahi | ||
| Plant Protection Research Institute, Agricultural Research Center, Giza, Egypt | ||
| Abstract | ||
| The persistence of pyridalyl, emamectin-benzoate, spinetoram, hexaflumuron, and chlorpyrifos on cotton (Gossypium barbadense, var. Giza 86) and castor bean (Ricinus communis) foliages under field conditions, via bio-determination of median lethal time (Lt50) values, and their efficacy against the 4th instar larvae of Spodoptera littoralis (Boisd.) laboratory strain were investigated. The local and systemic activities and fastness against washing with water of the tested insecticides on cotton and castor bean were studied as well. Pyridalyl residues were significantly the most persistent on castor bean and cotton plants with Lt50 values of 14.91 and 9.93 days, respectively. On the contrary, spinetoram had the least persistent residues on castor bean and cotton recording Lt50 of 0.20 and 1.06 days, respectively. With exception of pyridalyl, the tested insecticides were significantly more persistent on cotton than on castor bean plants. Pyridalyl and emamectin-benzoate proved to be the most effective against the 4th instar larvae of S. littoralis that fed on treated cotton plants. When the larvae were fed on treated castor bean plants, pyridalyl and hexaflumuron resulted in the superior percentages of larval mortality. The insecticides implicated in this study did not demonstrate any appreciable systemic activities in cotton or castor bean plants against the 4th instar larvae of S. littoralis, although they possessed strong local activities. The initial deposits of chlorpyrifos, pyridalyl, hexaflumuron, and emamectin-benzoate were significantly more stable on sprayed castor bean plants than on sprayed cotton plants versus elimination and washing with water. The initial deposit of spinetoram was completely unstable on sprayed cotton or castor bean plants. These results indicated that the kind of the treated host plant is very effective factor in toxicological properties of the tested insecticide and this could be useful in bio assay experiments design. | ||
| Keywords | ||
| Cotton; Castor bean; Spodoptera littoralis; Insecticides; persistence; Local and systemic activities; fastness | ||
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