LAUSR

BACKGROUND Pyridazine pyrazolecarboxamides (PPCs) are a novel insecticide class discovered and optimized at BASF. Dimpropyridaz is the first PPC to be submitted for registration and controls many aphid species as well as whiteflies and other piercing-sucking insects. RESULTS Dimpropyridaz and other tertiary amide PPCs are proinsecticides that are converted in vivo into secondary amide active forms by N-dealkylation. Active secondary amide metabolites of PPCs potently inhibit the function of insect chordotonal neurons. Unlike Groups 9 and 29 insecticides, which hyper-activate chordotonal neurons and increase Ca2+ levels, active metabolites of PPCs silence chordotonal neurons and decrease intracellular Ca2+ levels. Whereas the effects of Groups 9 and 29 insecticides require TRPV channels, PPCs act in a TRPV-independent fashion, without compromising cellular responses to Group 9 and 29 insecticides, placing the molecular PPC target upstream of TRPVs. CONCLUSIONS PPCs are a new class of chordotonal organ modulator insecticides for control of piercing-sucking pests. Dimpropyridaz is a PPC proinsecticide that is activated in target insects to secondary amide forms that inhibit the firing of chordotonal organs. The inhibition occurs at a site upstream of TRPVs and is TRPV-independent, providing a novel mode of action for resistance management. This article is protected by copyright. All rights reserved.