Assessment the Resistance Levels in Field Strain of Cotton Leafworm to some Insecticides | ||
| Alexandria Science Exchange Journal | ||
| Article 1, Volume 43, Issue 2, April 2022, Pages 179-185 PDF (248.94 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/asejaiqjsae.2022.229597 | ||
| Author | ||
| Gihan Fathy Ali* | ||
| Pesticides chemistry , Faculty of agriculture , Alexandria University | ||
| Abstract | ||
| This study was performed to assess the resistance levels in a cotton leafworm (CLW), Spodoptera littoralis (Boisd) field strain in comparison with a laboratory strain toward alpha-cypermethrin, chlorpyrifos, methoxfenozide, chlorantraniliprole, and chlorfluazuron. Their Ovicidal activity and residual toxicity against neonates were also evaluated. Glutathione S-transferases (GST) and total esterases activities of of 2nd and 4th larval instars treated with these insecticides were determined. The field strain exhibited different level of resistance where cypermethrin, chlorpyrifos, and methoxfenozide ratios (RR) were 12.7, 48.0, and 13.8, respectively for 2nd instar, while 4th instar is only resistant to cypermethrin, chlorpyrifos with RR of 120.8 and 19.0 compared to lab strain. Concerning the ovicidal and residual toxicity at the recommended field rate, cypermethrin, chlorpyrifos, chlorantraniliprole, and chlorfluazuron achieved mortality of treated eggs and neonates of lab strain 95.3, 98.9, 93.3, and 96.8%, respectively as well as 75.6, 70.0, 85.2 and 91.6%, respectively against field strain. However, methoxyfenozide showed a non-significant difference between lab and field strains. GST and esterases activities were significantly higher in the field strain compared with that of lab strain. It can be concluded that monitoring of insecticide resistance is a crucial step for the plant protection and resistance management programs. | ||
| Keywords | ||
| Cotton leafworm; Insecticide resistance; Glutathione S-transferases; total esterases | ||
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