Pesticide Science (1998) 54, 203-211

Christopher Howard Wearing (1998)
Cross-resistance between azinphos-methyl and tebufenozide in the greenheaded leafroller, Planotortrix octo
Pesticide Science 54 (3), 203-211
Abstract: Organophosphate(OP)-resistant greenheaded leafroller, Planotortrix octo, from Dumbarton, Central Otago, New Zealand, were tested for resistance to tebufenozide and azinphos-methyl. Colonies of P. octo were obtained in 1993 and 1995 by tethering virgin females of an OP-susceptible strain (S×S) in apple orchards at Dumbarton, where they mated with wild males, and then raising their progeny (S×D). To remove susceptible insects, first-instar larvae from these colonies were selected respectively four and three times with discriminating doses of azinphos-methyl (1993-94, direct spray) to create colony S×DSe(Az), or tebufenozide (1995-96, diet-sprayed residue) to produce S×DSe(Te).
Dosage mortality tests showed that S×D first-instar larvae were 2- to 4-times resistant to azinphos-methyl and 5- to 8-times resistant to tebufenozide at LD₅₀, compared to S×S. Tests with progeny of isofemale lines of S×D revealed two groups of insects, one 3·5-times resistant and the other 14-times resistant to tebufenozide. After selection, S×DSe(Az) larvae were 14-times resistant to azinphos-methyl and 13-times resistant to tebufenozide, compared to S×S. S×DSe(Te) larvae were 21-times resistant to azinphos-methyl and 76-times resistant to tebufenozide. Resistance of S×DSe(Te) to tebufenozide declined from 269-times at six days to 76-times, 36 days after first exposure. All tests results demonstrated the presence of resistance to azinphos-methyl and tebufenozide in the P. octo population and high cross-resistance between these chemicals. Selection with either chemical conferred resistance to the other. Continued use of mating disruption in a resistance management programme at Dumbarton is recommended.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Christopher Howard Wearing

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.
	Planotortrix octo	Apple (Malus)