|Elliott, Norman - Norm|
Submitted to: Southwestern Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/15/2007
Publication Date: 12/1/2007
Citation: Elliott, N.C., Mirik, M., Yang, Z., Dvorak, T., Rao, M., Michels, J., Walker, T., Catana, V., Phoofolo, M., Giles, K., Royer, T. 2007. Airborne multi-spectral remote sensing of Russian wheat aphid injury to wheat. Southwestern Entomologist. 32:213-219. Interpretive Summary: The Russian wheat aphid is a severe pest of wheat in the High Plains region of the United States. Remote sensing holds promise as a cost effective method for detecting Russian wheat aphid damage to wheat for pest management decision-making, but has not yet been thoroughly evaluated to determine if it will work for monitoring. We evaluated remote sensing based on reflected sunlight (multi-spectral remote sensing) for its ability to detect injury caused by the Russian wheat aphid to winter wheat in production fields. Four production wheat fields, two in southeastern Colorado and two in far western Oklahoma were selected to test multi-spectral remote sensing for detecting Russian wheat aphid injury to wheat. In each field, plant damage was determined and multi-spectral imagery was obtained from an aircraft equipped with a digital camera capable of taking multi-spectral images. Areas within the field with wheat plants injured by Russian wheat aphids was consistently detected and differentiated from areas without injury. Based on the study it appears to be feasible to use remote sensing to identify and monitor Russian wheat aphid infested wheat fields. However, a great deal of research and development will be needed to develop remote sensing to the point where it is an accurate and cost effective tool for that purpose.
Technical Abstract: The Russian wheat aphid (RWA) is a severe pest of wheat in the High Plains region of the United States. Remote sensing could be effective for detecting RWA infestations for pest management decision-making purposes. We evaluated an airborne multi-spectral remote sensing system for its ability to differentiate varying levels of injury caused by RWA infestation in winter wheat fields. Two fields located in southeastern Colorado were studied in spring 2004, and two fields located in far western Oklahoma were studied in spring 2005. In each field, the proportion of wheat stems damaged by RWA was measured in 20 to 24 3x3 m plots with varying levels of RWA infestation. Prior to sampling plots, multi-spectral imagery was obtained using an SSTCRIS® multi-spectral imaging system mounted NADIR in a Cessna 172 aircraft. The multi-spectral data were compared with the intensity of damage to wheat plants caused by RWA. Correlations between vegetation indices calculated from the multi-spectral data with the proportion of RWA damaged wheat tillers per plot were negative for all vegetation indices. Regressions of vegetation indices versus the proportion of RWA damaged wheat tillers per plot were usually significant and had negative slopes. However, slopes and intercepts of regressions differed significantly among fields. Any one or a combination of differences in time of day, atmospheric conditions, edaphic factors (e.g. soil type and soil moisture), and possibly other factors could have caused the differences observed in regressions among fields.