RESISTANCE MONITORING OF COTTON LEAF WORM, SPODOPTERA LITTORALIS (BOISDUVAL) (LEPIDOPTERA: NOCTUIDAE) AGAINST CERTAIN ALTERNATIVE INSECTICIDES OF FOUR DIFFERENT FIELD POPULATIONS IN EGYPT | ||||
| Journal of Biological Chemistry and Environmental Sciences | ||||
| Volume 14, Issue 1, March 2019, Page 319-333 PDF (1.05 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/bces.2019.425754 | ||||
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| Abstract | ||||
| Cotton leaf worm, Spodoptera littoralis (Boisd.) is a key pest affecting many field crops and vegetables in Egypt. Its control depends mainly on the application of various insecticides with different modes of action. In the current study, susceptibility of four field collected populations were tested to six insecticides for three consecutive years (2015-2017). These insecticides included insect growth regulators (IGRs), spinosad and emamectin benzoate. These insecticides at their variable concentrations were tested against 2-nd instar larvae of S. littoralis under laboratory conditions. Comparing with laboratory strain, field-collected RESISTANCE MONITORING OF COTTON LEAF WORM320 populations showed a susceptibility to very low levels of resistance to the tested IGRs. Resistance ratio (RR) recorded (1.23– 5.46-fold) to lufenuron, 2.16 – 5.57-fold to flufenoxuron, 1.69 –6.78 fold to chlorfluazuron and 0.45-2.46-fold to hexaflumuron. Furthermore, emamectin benzoate showed very low to low level of resistance (2–10 fold), in line with spinosad which recorded 1.36 - 3.40-fold. Concerning the cross-resistance between the tested insecticides was explored throughout pairwise correlation analysis. The obtained data indicated a significant correlation between the tested IGRs except for lufenuron and hexaflumuron. In contrast, spinosad showed no correlation with all other tested insecticides with reference to the negative correlation with emamectin benzoate. Similarly, emamectin benzoate showed non- significant correlation to all the tested insecticides except for chlorfluazuron. So, rotation of insecticides with none and negative cross- resistance can carry out effective control of the pest and sustain pest susceptibility to recommended insecticides. | ||||
| Keywords | ||||
| Key words: Spodoptera littoralis; insect growth regulators (IGRs); spinosad; emamectin benzoate; resistance; pairwise correlation | ||||
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