Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2003
Publication Date: 10/23/2003
Citation: Abel, C.A., Pollan, M.R. 2003. Field resistance of bacillus thuringiensis transformed maize to fall armyworm (lepidoptera: noctuidae) and southwestern corn borer (lepidoptera: crambidae) leaf feeding. J. Entomol. Sci. 38(4): 377-384.
Interpretive Summary: The fall armyworm and southwestern corn borer cause economic damage to corn grown in the southeastern United States. Bt corn hybrids are available to growers for control of theses and other caterpillar pests. In the southern United States, many growers plant Bt hybrids to protect against damage caused by the southwestern corn borer, but the effectiveness against southwestern corn borer has not been well documented. For this study, the seven Bt hybrids were tested for their control of leaf feeding fall armyworm and southwestern corn borer. Based on the development of the larvae on the Bt corn plants, the fall armyworm was more tolerant of the insecticidal proteins in Bt than the southwestern corn borer. Bt corn should be effective in controlling the southwestern corn borer. Increasing the level of Bt insecticidal proteins or combining other control methods along with the use of Bt hybrid corn may be necessary to achieve suitable control of fall armyworm.
Technical Abstract: The fall armyworm, Spodoptera frugiperda (J. E. Smith), and the southwestern corn borer, Diatraea grandiosella (Dyar), can cause economic damage to maize grown in the southeastern United States. Maize hybrids have been transformed to express insecticidal crystalline proteins from Bacillus thuringiensis (Bt) Berliner that are resistant to lepidopteran pests are commercially available. The field efficacy of seven Bt hybrids were tested for control of leaf feeding fall armyworm and southwestern corn borer. All Bt hybrids performed better than their conventional near-isolines for control of both insects. In general, the Bt hybrids provided intermediate resistance to the fall armyworm and high resistance to the southwestern corn borer. There was no difference in expression of insecticidal proteins among the Bt hybrids. Bt hybrids should be advantageous for the production of maize in areas that are affected by southewestern corn borer. The moderate level of resistance in the Bt hybrids to fall armyworm should be further examined to determine if amplifying the expression of insecticidal proteins of integrating other control methods along with the use of current Bt hybrid maize is needed to protect the crop from yiled reduction by this pest.