Journal of Economic Entomology (1996) 89, 15-20

Elisabetta Rossi and Silvano Presciuttini (1996)
Development of insecticide resistance in Piophila casei (Diptera: Piophilidae) strains selected with low doses of deltamethrin
Journal of Economic Entomology 89 (1), 15-20
Abstract: Two populations of the cheese skipper, Piophila casei (L.), were sampled. The 1st was from a sheep farm where no chemical was ever applied; the 2nd was present in a ham factory where chemical treatment with pyrethroids was applied in the past against house flies, Musca domestica L., and Dermestid beetles. A substantial difference between their resistance to deltamethrin was observed (LC₅₀ = 11.56 versus 68.08 µg/cm² for females and 1.11 versus 4.20 µg/cm² for males, respectively). Laboratory strains were established from both populations and were selected at constant rates for up to 20 generations (2, 4, and 7.3 ppm for the strains derived from the 1st population and 40 ppm for that selected from the 2nd population). Males and females of both strains showed an increase in LC₅₀ (tested at the 5th and 19th or 10th generation), except when females were selected at the lowest rate (2 ppm). At the end of the trial, slopes of logit regressions were substantially steeper in strains selected at higher rates, suggesting that the effect of the insecticide was to reduce resistance variance. Crosses between unselected and selected strains were done. Results of survival analysis in F₁ hybrids were analogous for males and females and were similar in both reciprocal crosses. LC₅₀s were intermediate between those of the parental strains.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Elisabetta Rossi

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.
	Piophila casei		Italy