Larval Susceptibility of an Insecticide-Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae) Population to Soil Insecticides: Laboratory Bioassays, Assays of Detoxification Enzymes, and Field Performance

Characterization of General Esterases from Methyl Parathion-Resistant and -Susceptible Populations of Western Corn Rootworm (Coleoptera: Chrysomelidae)

“…This difference is consistent with previous results from topical bioassays with the same resistant populations, in which third instars averaged 1.5-fold higher methyl parathion resistance ratios relative to adults , Wright et al 2000. Because both larvae and adults exhibited elevated esterase activities in resistant populations, it is apparent that selection of one life stage has the potential to impact resistance in another stage (i.e., selection of adults equates to selection of all life stages).…”

“…Elevated esterase activities toward the model substrates ␣-and ␤-naphthyl acetate were exhibited in both larval and adult stages of Phelps and York county populations (Wright et al 2000). A consistent correlation between elevated esterase activity as determined by native polyacrylamide gel electrophoresis and methyl para-thion resistance among Nebraska western corn rootworm populations has been documented previously (Zhou et al 2002).…”

“…1D). At higher pH levels (Ͼ7.4), color formation after staining with ␤-naphthyl acetate was unstable (data not shown), and therefore, pH 7.0 was chosen for routine measurement of esterase activity as described previously by Miota et al (1998) and Wright et al (2000).…”

“…Because both larvae and adults exhibited elevated esterase activities in resistant populations, it is apparent that selection of one life stage has the potential to impact resistance in another stage (i.e., selection of adults equates to selection of all life stages). However, the resistance seems to be relatively speciÞc to methyl parathion because the Þeld performance of other soil insecticides, including other organophosphates, does not seem to be signiÞcantly affected by resistance (Wright et al 2000).…”

A Core Set of Microsatellite Markers for Western Corn Rootworm (Coleoptera: Chrysomelidae) Population Genetics Studies

“…In addition, this pest is becoming more difÞcult to manage in parts of its range in North America because of the development of resistance to chemical insecticides (Meinke et al 1998, Wright et al 2000 and to crop rotation (Levine et al 2002). Transgenic Bt corn expressing the Cry3Bb1 toxin from Bacillus thuringiensis has proven very effective in the United States (Al-Deeb and Wilde 2005), but there is concern that D. v. virgifera could evolve resistance to this product as well.…”