The novel pyridazine pyrazolecarboxamide insecticide dimpropyridaz inhibits chordotonal organ function upstream of TRPV channels

Pest Manag Sci. 2023 May;79(5):1635-1649. doi: 10.1002/ps.7352. Epub 2023 Mar 1.

Abstract

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 Group 9 and 29 insecticides, which hyperactivate chordotonal neurons and increase Ca2+ levels, active metabolites of PPCs silence chordotonal neurons and decrease intracellular Ca2+ levels. Whereas the effects of Group 9 and 29 insecticides require TRPV (Transient Receptor Potential Vanilloid) 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 insecticide 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. © 2023 BASF Corporation. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Keywords: Afidopyropen; Bemisia tabaci; Drosophila melanogaster; PPC; Periplaneta americana; flonicamid; nicotinamide; pymetrozine; pyrifluquinazon.

MeSH terms

  • Amides / pharmacology
  • Animals
  • Aphids*
  • Insecta
  • Insecticide Resistance
  • Insecticides* / pharmacology

Substances

  • Insecticides
  • Amides