|Shepard, Merle - CLEMSON UNIV.|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 18, 2005
Publication Date: August 1, 2005
Citation: Farrar, R.R., Shapiro, M., Shepard, M.B. 2005. Enhanced activity of the nucleopolyhedrovirus of the fall armyworm (lepidoptera:noctuidae) on bt- transgenic and nontransgenic sweet corn through the use of a fluorescent brightener and a feeding stimulant. Environmental Entomology. 34:825-832. Interpretive Summary: The fall armyworm is a major pest of corn throughout the warmer parts of the Americas. Corn plants that been genetically engineered with toxins from the bacterium Bacillus thuringiensis (Bt) are resistant to a variety of caterpillars, such as the corn earworm, but they are generally not very resistant to the fall armyworm. Bt corn does kill some fall armyworms, but many survive to damage the crop. Bt corn may thus still need additional treatments to control this pest. There is a natural virus that kills fall armyworm caterpillars. It is harmless to people, wildlife, and beneficial insects such as bees. We previously found that this virus kills fall armyworms equally well on both Bt and non-Bt sweet corn. We then found that a feeding stimulant, Coax, and a virus enhancer, Blankophor P167, both increase the number of fall armyworms killed by the virus. They also seem to work equally well on Bt and non-Bt corn. The virus, with Coax and/or Blankophor P167, could provide the additional control needed to protect Bt corn from damage by the fall armyworm. We expect this information to be used by other scientists developing better and safer ways to control the fall armyworm. We will also use the information as a basis for testing the virus in the field. This information will lead to improved insect control while also reducing insecticide use and the problems of environmental contamination and worker exposure
Technical Abstract: The effects of a nutrient-based feeding stimulant, Coax, and of a stilbene-based optical brightener, Blankophor P167, on the activity of the nucleopolyhedrovirus of the fall armyworm, Spodoptera frugiperda (J. E. Smith), (SfMNPV) on transgenic sweet corn, Zea mays (L.), expressing a CryIA(b) toxin from Bacillus thuringiensis (Berliner), were studied in the laboratory. Coax and Blankophor P167 both increased virus-induced mortality. The effects of both materials did not differ between transgenic and non-transgenic corn. The greatest increase in virus-induced mortality occurred when Coax and Blankophor P167 were used together; the effect of combining these materials was greater than additive. Neither material affected the percentage of larvae killed by the CryIA(b) toxin.