ASSESSING THE RATE OF EVOLUTION OF RESISTANCE IN DIAMONDBACK MOTH, Plutella xylostella L. (LEPIDOPTERA: PLTELLIDAE) AGAINST NEWER SELECTED INSECTICIDES
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Date
2017-06
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University of Horticulture Sciences Bagalkot. (College of Horticulture, Bengaluru).
Abstract
The Diamondback moth (DBM), Plutella xylostella L. is one of the key insect pests of crucifers. The study was conducted to generate a baseline susceptibility data for newer selected insecticides, to assess the current status of insecticide resistance in DBM to newer selected insecticides and to observe the susceptibility of succeeding generations of DBM to different insecticides under laboratory conditions. The bioassay of newer insecticides was conducted against third instar larvae of DBM sampled from Bengaluru, Kolar and Chikkaballapura. The results of study exhibited variation in median lethal concentration (LC50) across insecticides for single population and also across the populations. The LC50 value of Bengaluru population was highest for fenvalerate 20 EC (11.90 μg a.i. ml-1) and lowest for emamectin benzoate (2.05 μg a.i. ml-1). The Kolar population recorded highest for dichlorvos 76 EC (14.08 μg a.i. ml-1) and lowest for cyantraniliprole 10.26 OD (2.67 μg a.i. ml-1). Similarly, for Chikkaballapura population it is highest for dichlorvos 76 EC (13.93 μg a.i. ml-1) and lowest for emamectin benzoate 5 SG (1.53 μg a.i. ml-1). The mean LC50 values were varied across the population and mean LC50 was highest for kolar population, which was followed by Bengaluru and Chikkaballapura population. Similarly, the mean LC50 were also varied across insecticides and highest mean LC50 was recorded for dichlorvos 76 EC and lowest mean was for emamectin benzoate 5 SG insecticide. The mean resistance ratios were varied across populations and Bengaluru, Kolar and Chikkaballapura recorded 1.789±0.636, 1.93±1.09 and 1.499±0.493 folds respectively. In brief, this clearly indicated that the rate of evolution of resistance in P. xylostella was varied across insecticides for single population and also across geographical locations.