author(s)
Meghana C, Jayappa J, N Aswathanarayana Reddy, V Devappa, V Sridhar and Jyothi Kattegoudar

abstract
The Study was conducted to assess the variations in relative susceptibility levels among the populations of diamondback moth in major cabbage growing areas of South Karnataka. The LC₅₀ values were varied across insecticides for single population and also across the populations of geographical locations. The LC₅₀value of Bengaluru, Kolar and Chikkaballapura populations recorded highest for dichlorvos 76 EC (15.63, 31.82 and 22.51 μg a.i. ml^-1) and the lowest LC₅₀value of Bengaluru, Kolar and Chikkaballapura populations recorded for emamectin benzoate 5 SG (3.13 μg a.i. ml^-1), cyantraniliprole 10.26 OD (4.48 μg a.i. ml^-1) and Spinosad 45 SC (2.48 μg a.i. ml^-1) was found to be highly toxic to the third instar larvae of P. xylostella. This clearly indicated that the rate of evolution of resistance in P. xylostella was varied across insecticides and also across geographical locations.