Submitted to: Journal of Economic Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/12/2004
Publication Date: 2/1/2005
Citation: Gore, J., Adamczyk Jr, J.J., Blanco, C.A. 2005. Selective feeding of tobacco budworm and bollworm (lepidoptera: noctuidae) on meridic diet with different concentrations of bacillus thuringiensis berliner proteins. Journal of Economic Entomology. Interpretive Summary: Laboratory experiments were conducted to evaluate the behavioral respone of bollworm and tobacco budworm larvae to the insecticidal proteins in Bollgard and Bollgard II cottons. Both bollworm and tobacco budworm avoided all concentrations of the Cry1Ac protein found in Bollgard cotton. In addition, bollworms selectively fed on diet with low concentrations of Cry1Ac compared to diet with high concentrations of Cry1Ac. Tobacco budworms avoided all concentrations of Cry1Ac. Avoidance of the Cry2Ab protein, the additional protein found in Bollgard II, was not as great as that observed with Cry1Ac. Bollworms and tobacco budworms did not show a preference for non-treated diet or diet treated with Cry1Ab. This information will be important for optimizing scouting procedures and management of bollworms and tobacco budworms in transgenic cottons.
Technical Abstract: Laboratory experiments were conducted to evaluate the behavior of bollworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (F.), larvae on meridic diet with different concentrations of the Cry1Ac and Cry2Ab proteins from Bacillus thuringiensis kurstaki Berliner. The proteins used in these experiments are the ones in commercially available Bollgard(R) and Bollgard II(R) cottons. Both bollworms and tobacco budworms selectively fed on non-treated diet compared to diet treated with Cry1Ac. In addition, bollworms exhibited a concentration response with Cry1Ac. In general, bollworms selected diet with low concentrations of Cry1Ac compared to diet with higher concentrations of Cry1Ac. For Cry2Ab, the avoidance was not as great as that observed for Cry1Ac. Based on results from no-choice assays, the Cry1Ac and Cry2Ab concentrations used in choice assays represented a wide range of biological activity on both species. The lower concentrations provided low levels of mortality; while, the higher concentrations provided high levels of mortality. Also, the developmental times of larvae were longer at higher concentrations of both proteins. These data provide important information about the behavioral response of key cotton pests to the B. thuringiensis proteins found in commercially available transgenic cottons. This information will be important to develop accurate scouting and management procedures for Bollgard and Bollgard II cottons.