Abstract:

The field diamondback moth, Plutella xylostella collected from Nanjing was found to be resistant to deltamethrin (24.69-fold tested by leaf dipping). But it was still sensitive to phoxim, chlorpyrifos, fipronil, spinosad and tebufenozide. PBO showed significant synergism to deltamethrin in the resistant moth. Laboratory breeding revealed that the deltamethrin resistance decreased quickly when the diamondback moth was reared without contact with insecticides, and kept in low resistance level after breeding for ten generations. Based on these results, it was suggested that rotational use of effective insecticides and using pyrethroid together with PBO should be rational for management of insecticide resistance in this pest.

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Key words: Plutella xylostella, deltamethrin, insecticide resistance, pesticide application strategy