Abstract
The mealybug Phenacoccus solenopsis is a destructive pest of cotton with the potential to develop resistance to most chemical classes of insecticides. Six populations of P. solenopsis from cotton crops at six different locations in Pakistan were evaluated for resistance to selected organophosphate and pyrethroid insecticides. Resistance ratios (RRs) at LC50 were in the range of 2.7–13.3 fold for chlorpyrifos, 11.6–30.2 fold for profenofos and for the three pyrethroids tested were 10.6–46.4 for bifenthrin, 5.8–25.2 for deltamethrin and 4.1–25.0 for lambda-cyhalothrin. This is the first report of resistance to organophosphate and pyrethroid insecticides in Pakistani populations of P. solenopsis. Regular insecticide resistance monitoring programs are needed to prevent field control failures. Moreover, integrated approaches including the judicious use of insecticides and rotation of insecticides with different modes of action are needed to delay the development of insecticide resistance in P. solenopsis.
•Phenacoccus solenopsis is a destructive pest of cotton with potential to develop resistance against various insecticides.•First report of resistance to organophosphates and pyrethroids in six populations of P. solenopsis from Pakistan.•RR ranged from 2.7 to13.3 fold for chlorpyrifos and 11.6 to 30.2 fold for profenofos.•RR ranged from 10.6 to 46.4 for bifenthrin, 5.8 to 25.2 for deltamethrin and 4.1 to 25.0 fold for lambda-cyhalothrin.•Effective resistance management strategies are required to prevent resistance development.