Bulletin of Entomological Research (2011) 101, 177-185

G.A.R. Silva and A.S. Lapenta (2011)
Genetic variability in esterases and the insecticide resistance in Brazilian strains of Oryzaephilus mercator and Oryzaephilus surinamensis (Coleoptera: Silvanidae)
Bulletin of Entomological Research 101 (2), 177-185
Abstract: Oryzaephilus mercator and O. surinamensis are stored grains and processed food pests, the latter being responsible for major economical losses. Polyacrylamide gel electrophoresis was used to analyse esterase patterns during insect development. Seven esterases, three cholinesterases, two carboxylesterases and two acetylesterases, were identified in O. mercator, one of which was proper to adults. Five esterases, of which four were cholinesterases, occurred in O. surinamensis. Strains of O. mercator and O. surinamensis were also exposed to malathion and chlorpyrifos-methyl. According to the LC₅₀ estimates, OmLC-M and OmLA strains of O. mercator and OsLB strain of O. surinamensis were the most resistant to both insecticides. However, higher sensitivity to malathion and chlorpyrifos-methyl has also been verified in some of its esterases. Cholinesterases OmEST-1 and OsEST-5 seem to be involved in this resistance. These results suggest that organophosphate tolerance may be related to genetic variability in esterase isoenzymes.
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Link to article at publishers website

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.
	Oryzaephilus surinamensis	Stored grain
	Oryzaephilus mercator	Stored grain