Profenophos Resistance in Brinjal Shoot and Fruit Borer Leucinodes orbonalis Guenee

The present experiment was carried out in Tamil Nadu to investigate the level of profenophos resistance in Leucinodes orbonalis Guenee populations from different locations. The median lethal concentration (LC₅₀) values was observed to vary from 54.72 to 287.83 ppm, with Dharmapuri and Theni exhibiting moderate resistance (LC₅₀ of 287.83 and 251.65 ppm, respectively), while Villupuram and Thiruvannamalai remained susceptible (LC₅₀ of 64.95 and 54.72 ppm, respectively). Resistance ratios, calculated against a susceptible population, varied across regions as Dharmapuri (11.61 fold), Theni (10.15 fold), Salem (6.99 fold), Coimbatore (6.26 fold), Tiruchirapalli (5.72 fold), Madurai (5.66 fold), Namakkal (5.37 fold), Dindigul (3.46 fold), Villupuram (2.62 fold) and Thiruvannamalai (2.21 fold). These findings highlight that populations of L. orbonalis developed low to moderate levels of resistance to profenophos and there is an urgency of implementing IPM strategies to curb the resistance.