Testing for Malathion Resistance in Field-collected Populations of Cryptolestes ferrugineus (Stephens) and Factors Affecting Reliability of the Tests
Authors: White, N. D. G.; Loschiavo, S. R.
Source: Journal of Economic Entomology, Volume 78, Number 3, June 1985 , pp. 511-515(5)
Publisher: Entomological Society of America
Abstract:Twenty-three strains of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), were collected in 1982 and 1983 from grain stored on farms in the prairie provinces of Canada and in Minnesota. Fifteen more strains of C. ferrugineus were collected from primary grain elevators within a 48-km radius of Winnipeg, Manitoba, in July and August 1984. A tentative discriminating concentration of 0.0091 mg (AI)/cm2 malathion on filter paper based on probit regressions for four laboratory strains was used to test the strains collected from farms. Individuals of 10 strains were not incapacitated at this concentration. A reliable discriminating concentration of 0.0130 mg/cm2 with 5-h exposure at 25°C gave complete knockdown of all 38 strains. None of the strains was resistant to malathion. Subsequent studies on the reliability of the resistance tests indicated that treated filter papers wrapped in aluminum foil could be stored for 24 weeks at −25 or 5°C with only slight loss of insecticide as determined by bioassay with the red flour beetle, Trtboltum castaneum (Herbst), and chemical assay. About 20 and 30% of malathion broke down at 25 and 30“C, respectively, during the 24-week storage period. Transfer by pipette of malathion dissolved in Risella oil resulted in malathion deposits 15 to 35% lower than intended, probably because of poor solubility of this insecticide in Risella oil and retention of oil in the pipette when following the standardized method. Acetone used as the primary solvent gave 94% of the intended deposit on filter papers. This information on the storage life of test filter papers and the actual deposit of insecticide on the papers will permit improvements and changes in methodology that will result in increased reliability of the resistance tests for future monitoring of C. ferrugineus strains.
Document Type: Research Article
Publication date: 1985-06-01
- Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.
- Editorial Board
- Submit a Paper
- Subscribe to this Title
- Information for Advertisers
- Visit this journal's homepage
- ingentaconnect is not responsible for the content or availability of external websites