Vol. 11, Special Issue 9 (2022)

Author(s):
Deshavath Anjali, SV Krishnamoorthy, M Murugan and S Jeyarani

Abstract:
The fall armyworm (FAW) Spodoptera frugiperda (JE Smith) is an invasive pest of maize in India. This pest reached epidemic proportions, causing enormous damage on the maize crop in several Indian states. The reliance on pesticides to control fall armyworm could lead to development of resistance in many of the Indian maize growing areas. Study was undertaken to assess the susceptibility of fall armyworm to three insecticides viz., chlorantraniliprole 18.5 SC, flubendiamide 480 SC and spinetoram 11.7 SC was determined by leaf disc bioassay. The LC₅₀ and LC₉₅ values of field population towards chlorantraniliprole 18.5 SC, flubendiamide 480 SC and spinetoram 11.7 SC were 6.93 and 16.40 µgmL^-1; 121.36 and 180.69 µgmL^-1 and 0.046 and 0.321 µgmL^-1 respectively. The susceptibility of field collected populations were compared with FAW population maintained in the laboratory without exposure to insecticides for 25 generations. Resistance ratio (RR₅₀) of the test insecticides viz., chlorantraniliprole 18.5 SC (2.24-fold), flubendiamide 480 SC (2.44-fold) and spinetoram 11.7 SC (1.64-fold) implied that flubendiamide 480 SC was showing more resistance compared to chlorantraniliprole 18.5 SC and Spinetoram 11.7 SC. Spinetoram 11.7 SC was more potent compared to other two insecticides based on relative potency ratio (REP).