Journal of Economic Entomology (1997) 90, 1462-1470

Carlos J. Perez, Anthony M. Shelton and Richard T. Roush (1997)
Managing diamondback moth (Lepidoptera: Plutellidae) resistance to foliar applications of Bacillus thuringiensis: Testing strategies in field cages
Journal of Economic Entomology 90 (6), 1462-1470
Abstract: Three resistance management strategies for field-sprayed commercial formulations of Bacillus thuringiensis Berliner subspecies were tested in field cages during the dry and rainy seasons of 1995 in Honduras. A local field population of Plutella xylostella (L.) with a 21-fold resistance to B. thuringiensis subsp. kurstaki (Javelin), but no resistance to B. thuringiensis subsp. aizawai (Xentari), was selected for 5-6 generations with 16 field applications of a high (1.12 kg/ ha) or low (0.3 kg/ ha) dose of Javelin, a high or low dose of javelin in the presence or absence of a refuge (25%), and Xentari (1.12 kg/ha). Resistance to Javelin increased ~1.9-4.4 times, but was significant only with the 1.12 kg/ha rate of javelin irrespective of the presence or absence of a refuge. Field selection with javelin at 0.3 kg/ha or Xentari did not cause a significant increase in resistance to B. thuringiensis subsp. kurstaki, nor did P. xylostella selected with Xentari evolve resistance to B. thuringiensis subsp. aizawai. During the same period, the LC50 of Javelin in P. xylostella left unselected did not decrease. Although the rate of resistance increase was lower for lower doses of Javelin, a smaller proportion of marketable cabbage was produced in comparison with higher doses of Javelin or Xentari. Our data suggest that the deliberate inclusion of a refuge may reduce the proportion of marketable produce, and may affect use of this resistance management strategy in both sprayed B. thuringiensis and transgenic crops expressing B. thuringiensis toxins.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Anthony M. Shelton

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
pesticide resistance of pest
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plutella xylostella		Honduras
Bacillus thuringiensis var. kurstaki (entomopathogen)	Plutella xylostella		Honduras
Bacillus thuringiensis var. aizawai (entomopathogen)	Plutella xylostella		Honduras