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Use of Spectral Vegetation Indices for Detection of European Corn Borer Infestation in Iowa Corn Plots
Citation:
Carroll, M., J. A. GLASER, R. L. Hellmich, T. E. Hunt, D. Calvin, K. Copenhave, AND J. Fridgen. Use of Spectral Vegetation Indices for Detection of European Corn Borer Infestation in Iowa Corn Plots. Presented at Entomological Society of America North Central Branch Meeting, Columbus, OH, March 24 - 27, 2008.
Impact/Purpose:
To inform the public.
Description:
Recently, corn grown for grain in the United States has increased from 28 million ha in 2006 to more than 35 million ha in 2007 with a production value of over $52 billion dollars. Transgenic corn expressing the plant incorporated protectant Bacillus thuringiensis toxin represented nearly 50% of the 2007 planted corn. Such large plantings of transgenic corn spread across wide geographical areas makes monitoring for development of insect pest resistance to the toxin challenging. Remote sensing potentially provides a means of reliably detecting plant stress related to insect feeding damage. During the 2004 and 2005 growing season in Iowa, we selected eleven spectral vegetation indices that emphasize foliar plant pigments and evaluated their ability to detect experimental plots of corn manually inoculated with Ostrinia nubilalis (Hübner) neonate larvae. These inoculations were timed to simulate infestation of corn by first and second flights of adult O. nubilalis. We found that multiple spectral vegetation indices were able to detect O. nubilalis inoculated plots in late August and early September. We propose that damage to corn plants from O. nubilalis larvae feeding and stem boring increases the rate of plant senescence causing detectable differences in plant biomass and vigor when compared to non-damaged plants. Further, we identified an approximate time frame of 5-6 weeks post-inoculation, when spectral differences of manually inoculated “second” generation O. nubilalis plots appear to peak. Also, our findings suggest that spectral vegetation indices targeting carotenoid and anthocyanin pigments may not be as effective as those targeting chlorophyll.