Journal of Economic Entomology (2006) 99, 1761-1767

Changlu Wang, Michael E. Scharf and Gary W. Bennett (2006)
Genetic basis for resistance to gel baits, fipronil, and sugar-based attractants in German cockroaches (Dictyoptera: Blattellidae)
Journal of Economic Entomology 99 (5), 1761-1767
Abstract: A gel bait-resistant Blattella germanica (L.) strain (Cincy) was collected in Cincinnati, OH, in 2003. This strain exhibited strong behavioral resistance to Avert (0.05% abamectin), Maxforce FC (0.01% fipronil), and Pre-Empt (2.15% imidacloprid) gel baits. Reciprocal mass crosses and back crosses between the Cincy strain and a susceptible strain (Jwax) were made and tested for their inheritance of resistance to Avert, Maxforce FC, and Pre-Empt gel baits. Topical assays comparing the parental and reciprocal-heterozygous strains indicated the resistance to fipronil was incompletely recessive. LD₅₀ and LD₉₀ values of the Jwax-male × Cincy-female strain were not significantly different from the Jwax-female × Cincy-male strain, suggesting no sex linkage in physiological fipronil resistance. Feeding assays revealed that F₁ reciprocal crosses were significantly less responsive to blank Avert and Maxforce FC baits (without active ingredients) than the susceptible strain. The Jwax-female × Cincy-male strain did not display significantly greater consumption of blank Avert and Maxforce FC baits relative to the Jwax-male × Cincy-female strain. In feeding assays with agar containing d-fructose, d-galactose, d-glucose, d-lactose, d-maltose, and d-sucrose, the crosses showed an intermediate feeding response to glucose compared with the Cincy and Jwax strains, and a similar response to other sugars compared with the Jwax strain. The Jwax-male × Cincy-female strain was significantly less responsive to glucose than the Jwax-female × Cincy-male strain. Mortality induced by Avert, Maxforce FC, and Pre-Empt gel baits against the F₆ Jwax-male × Cincy-female strain was 44.2 ± 6.8, 92.9 ± 2.1, and 78.7 ± 5.2%, respectively, indicating the resistance to Avert and Pre-Empt gel baits inherited by Cincy females was extremely stable. The F₆ Jwax-male × Cincy-female strain was significantly more resistant to Avert, Maxforce FC, and Pre-Empt than the F6 Jwax-female × Cincy-male strain. These findings suggest that behavioral resistance to gel baits has weak sex-linkage, with a greater degree of the resistance trait being inherited by female cockroaches. Alternatively, physiological resistance to fipronil has no sex-linkage, but it is nonetheless important to the complete resistance phenotype.
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Full text of article
Database assignments for author(s): Changlu Wang, Michael E. Scharf

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.
	Blattella germanica		U.S.A. (NE)