Efficacy of Artemisia judaica Extract and Certain Insecticides against Cotton Leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae)

Document Type : Original Article

Authors

1 Dept. of Cotton Pesticides Bioassay Research, Plant Protection Research Institute, Agricultural Research Center, Al Sabhia, Alexandria, Egypt

2 Dept. of Cotton Pesticides Bioassay Research, Plant Protection Research Institute, Agriculture Research Center, Alexandria, Egypt

3 Dept. of Pesticides Formulation, Central Agriculture Pesticide Laboratory, Agriculture Research Center, Alexandria, Egypt.

Abstract

Toxicity, feeding indices and residual efficacies of ethanol extract of Artemisia judaica and some synthetic insecticides were investigated alone and in combinations against 2nd instar larvae of Spodoptera littoralis. The LC50s of chromafenozide, fipronyl, and pyridalyl were (0.025 and 0.016 mg L-1), (0.140 and 0.065 mg L-1), and (0.127 and 0.012 mg L-1) at 72 and 96 hrs, respectively. A. judaica extracts had LC50s (9482.99 and 2839.30 mg L-1), LC25s (3011.15 and 706.82 mg L-1), and LC10s (1072.27 and 202.19 mg L-1) at 72 and 96 hrs, respectively. GC-MS analysis of this extract included fatty acids (51.5 %), eucalyptol (3.64 %), tetraneurin-A (2.84 %), coumarin (2.08 %) and flavone (0.81 %). All treatments submitted tests of anti-feedant activity, relative consumption rate, relative growth rate, and efficiency of conversion of ingested food were more affected at 96 hrs of exposure. In the laboratory, potentiation effects appeared in binary mixtures of for chromafenozide (LC50) with A. judaica (LC10) with CTFs (21.74 and 20.83) and with A. judaica (LC25) (42.11 and 23.33) after 72 and 96 hrs of exposure, respectively. Fipronyl (LC50) + A. judaica (LC25)had additive effects with CTFs of -17.24 and 6.67 after 72 and 96 hrs of exposure, respectively. Oppositely, fipronyl (LC50) + A. judaica (LC10)and all mixtures of pyridalyl + A. judaica had antagonistic effects. The highest overall mean mortality over 16 days in semi-field experiments of the 2nd instar larvae exposed 96 hrs to A. judaica (706.82 mg L-1) tank mixed with 0.5 FRs of fibronil and chromafenozide were (77.00 and 64.00 %) and (75.50 and 68.50 %) in seasons of 2017 and 2018, respectively. The residual efficacies of these mixtures possessed prolonged times and higher toxicity compared to their FR alone. The insecticidal roles related to phyto-components of this extract were discussed. 

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