PERFORMANCE OF TRANSGENIC (BT) CORN HYBRIDS IN MISSOURI FOR INSECT CONTROL AND YIELD

Authors: BARRY, B - RETIRED ARS; Darrah, Larry; HUCKLA, D - MO VALLEY AGRIC SERVICES; Antonio, Arnulfo; SMITH, G - UNIVERSITY OF MISSOURI; O'DAY, M - UNIVERSITY OF MISSOURI

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2000
Publication Date: 7/10/2000
Citation: Barry, B.D., Darrah, L.L., Huckla, D.L., Antonio, A.Q., Smith, G.S., O'Day, M.H. 2000. Performance of transgenic (bt) corn hybrids in missouri for insect control and yield. Journal of Economic Entomology. V.93(3):993-999.

Interpretive Summary: Bt insecticide formulations have been registered for crop use since 1961. These insecticides were developed from a naturally-occurring bacterium and are considered safe for the user and the environment. Biotechnology has advanced the use of this material to control lepidopteran insects. This "gene" allows the plant to internally produce an insecticidal crystal protein which protects the plant. Transgenic Bt hybrid corn has been marketed since 1996. The objective of the studies reported here is to show the efficacy of Bt hybrids for controlling stalk borers attacking corn in the United States, and to compare the yields of the various Bt hybrids. Both generations of European and the second-generation of southwestern corn borer were effectively controlled, but the Bt hybrids varied in degree of control. Hybrids from Ciba Seeds, DEKALB, and Mycogen had more European corn borer tunneling than those from Novartis or Cargill, and this was attributed to the different transgenic events involved. The Bt-transformed hybrids had virtually no leaf-feeding damage and less tunneling than the non-Bt hybrids. All of the non-Bt hybrids had leaf-feeding damage and stalk tunneling from both insects. When insect damage was significant, and in some evaluations where damage was not significant, differences in yields among Bt vs. non-Bt hybrids were observed. No significant insect population differences were observed for five genera of beneficial insects for Bt vs. non-Bt hybrids. The impact of this research is that we showed seedmen, agronomists, and farmers that hybrids with the Bt gene provide an effective, environmentally-friendly means of control for corn borers.

Technical Abstract: The efficacy of Bt-transformed corn (Zea mays L.) hybrids compared to comparable non-transformed corn hybrids for controlling first- and second- generation European (Ostrinia nubilalis Hubner), and second-generation southwestern corn borer (Diatraea grandiosella Dyar), was determined. Yield comparisons were obtained from the same plots of corn hybrids. Both generations of European and the second-generation of southwestern corn borer were effectively controlled, but the Bt hybrids varied in degree of control. Hybrids from Ciba Seeds, DEKALB, and Mycogen had more European corn borer tunneling than those from Novartis or Cargill, and this was generally ascribed to different transgenic events. The Bt-transformed hybrids had virtually no leaf-feeding damage and less tunneling than the non-Bt corn hybrids. Some Bt corn hybrids had no tunneling, while other Bt hybrids had a small amount of tunneling. All of the non-Bt hybrids had significant leaf-feeding damage and stalk tunneling from both insects. Only three live European corn borer larvae (stunted) were found in the Bt corn hybrids while splitting stalks to assess tunnel length. When insect damage was significant, and in some evaluations where damage was not significant, differences in yields among hybrids were observed. No significant insect population differences were observed for five genera of beneficial insects for Bt vs. non-Bt corn hybrids. Corn hybrids that have been transformed with the Bt gene provide an effective means of control for corn borers and efforts focused on maintenance of technology durability are warranted.