Pest Management Science (2009) 65, 404-412

Pieter Van Nieuwenhuyse, Thomas Van Leeuwen, Jahangir Khajehali, Bartel Vanholme and Luc Tirry (2009)
Mutations in the mitochondrial cytochrome b of Tetranychus urticae Koch (Acari: Tetranychidae) confer cross-resistance between bifenazate and acequinocyl
Pest Management Science 65 (4), 404-412
Abstract: BACKGROUND: Resistance of Tetranychus urticae Koch to bifenazate was recently linked with mutations in the mitochondrial cytochrome b Q_o pocket, suggesting that bifenazate acts as a Q_o inhibitor (Q_oI). Since these mutations might cause cross-resistance to the known acaricidal Q_oI acequinocyl and fluacrypyrim, resistance levels and inheritance patterns were investigated in several bifenazate-susceptible and bifenazate-resistant strains with different mutations in the cd1 and ef helices aligning the Q_o pocket.
RESULTS: Cross-resistance to acequinocyl in two bifenazate-resistant strains was shown to be maternally inherited and caused by the combination of two specific mutations in the cytochrome b Q_o pocket. Although most investigated strains were resistant to fluacrypyrim, resistance was not inherited maternally, but as a monogenic autosomal highly dominant trait. As a consequence, there was no correlation between cytochrome b genotype and fluacrypyrim resistance.
CONCLUSIONS: Although there is no absolute cross-resistance between bifenazate, acequinocyl and fluacrypyrim, some bifenazate resistance mutations confer cross-resistance to acequinocyl. In the light of resistance development and management, high prudence is called for when alternating bifenazate and acequinocyl in the same crop. Maternally inherited cross-resistance between bifenazate and acequinocyl reinforces the likelihood of bifenazate acting as a mitochondrial complex III inhibitor at the Q_o site.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Thomas Van Leeuwen, Luc Tirry

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae