Fitness Costs in Diamondback Moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) Resistant to Lufenuron, A Chitin-Synthesis Inhibitor Insecticide

Abstract

Resistance to insecticides is one of the main factors that makes it difficult to control the diamondback moth, Plutella xylostella, on Brassica crops. Recurrent control failures lead to more frequent insecticide applications, use of higher doses, and decreased yield. This results in environmental pollution, increased population resistance, and economic loss. Studies that elucidate the characteristics of resistance are necessary to improve pest control strategies and overcome this problem. Resistance, in turn, carries a fitness cost, which impairs the biological characteristics, or fitness, of the resistant population compared to a susceptible population in environments without insecticides. Thus, the present study evaluated the fitness cost of resistance to lufenuron in a P. xylostella population, as well as the stability of this resistance in the resistant population without selection pressure for four generations. As a result, we observed that the resistant population demonstrated greater resistance than the susceptible population of P. xylostella, as well as a low fitness cost which was associated with lufenuron resistance. This information supports the adoption of strategies such as preserving refuge areas near crops for susceptible insects and natural enemies, helping to dilute resistance in the field, as well as other strategies.