title: Susceptibility of dipel-resistant and -susceptible Ostrinia nubilalis (Lepidoptera: Crambidae) to individual Bacillus thuringiensis protoxins.
abstract: Dipel-resistant and -susceptible strains of Ostrinia nubilalis (Hübner) were evaluated for larval mortality and growth inhibition when fed diets containing individual Bacillus thuringiensis protoxins. Resistance ratios for four of the protoxins in Dipel (Cry1Aa, Cry1Ab, Cry1Ac, and Cry2Aa) were 170-, 205-, 524-, and > 640-fold, respectively, considerably higher than the 47-fold resistance to Dipel. The Dipel-resistant strain was 36-fold resistant to Cry1Ba, a protoxin not present in Dipel. Another non-Dipel protoxin, Cry1Ca, did not cause significant mortality for either resistant or susceptible larvae with doses as high as 1.0 mg/ml. In an evaluation of larval growth inhibition, resistance to Cry1Aa, Cry1Ab, Cry1Ac, and Cry1Ba was significant at concentrations of 0.054 and 0.162 microg/ml. However, growth inhibition with Cry2Aa was not significant at either dose. These data provide information on the spectrum of resistance and cross-resistance to individual Cry protoxins in this strain.
authors.affiliation: Department of Entomology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Huarong
authors.initials: H
authors.lastname: Li
authors.forename: Brenda
authors.initials: B
authors.lastname: Oppert
authors.forename: Randall A
authors.initials: RA
authors.lastname: Higgins
authors.forename: Fangneng
authors.initials: F
authors.lastname: Huang
authors.forename: Lawrent L
authors.initials: LL
authors.lastname: Buschman
authors.forename: Kun Yan
authors.initials: KY
authors.lastname: Zhu
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007305:Insecticide Resistance; D007306:Insecticides; D007814:Larva; D007915:Lepidoptera; D011498:Protein Precursors
chemical_list: D000083722:Bacillus thuringiensis Toxins; C029103:Bacillus thuringiensis protoxin; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D011498:Protein Precursors; C030956:insecticidal crystal protein, Bacillus Thuringiensis