Submitted to: International Journal of Agricultural and Biological Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 2013
Publication Date: March 31, 2013
Citation: Lan, Y., Zhang, H., Hoffmann, W.C., Lopez, J. 2013. Spectral response of spider mite infested cotton: Mite density and miticide rate study. International Journal of Agricultural and Biological Engineering. 6:48-52. Interpretive Summary: Precision agricultural systems that combine site-specific detection and treatment capability will provide farmers with the potential to produce crops more economically and efficiently using fewer agrochemicals. However, new tools are needed to identify the location and severity of pest infestations. We investigated the capability to identify the severity of spider mite infestations associated with various levels of crop damage to determine effective rates of miticide. Through analysis of remote sensing data (including visible and near-infrared wavelengths) obtained from plants grown in greenhouses, we demonstrated that a half-rate of a commercial miticide could control spider mite-infested plants effectively. Results of this investigation will lead to development of precision agriculture tools that farmers can use for environmentally-friendly crop production with minimum agrochemical inputs and maximum crop yields.
Technical Abstract: Two-spotted spider mites are important pests in many agricultural systems. Spider mites (Acari: Tetranychidae) have been found to cause economic damage in corn, cotton, and sorghum. Adult glass vial bioassays indicate that Temprano™ (abamectin) is the most toxic technical miticide for adult two-spotted spider mite. From an aerial application standpoint, additional research is needed to identify aerial application parameters for this miticide. The objective of this study was to investigate spectral response of spider mite-infested cotton plants with different density levels of mites and treated with different rates of miticide. Results showed significantly different spectral signatures of cotton plants infested with different density levels of mites. By treating mite-infested cotton plants with five different Temprano rate treatments, control, one-eighth, one-fourth, one-half, and full rates, spectral reflectance curves were found to be significantly different. Four wavelengths, 550, 560, 680 and 740 nm, were important for detecting the spectral differences among mite-infested cotton plants treated with various rates of Temprano. Normalized Difference Vegetative Index imagery was able to detect different levels of cotton plant damage. Half-rate application of Temprano controlled mite-infested plants as effectively as the full-rate application. These findings may lead to reduced cost and quantity of miticides used to maintain effective crop production and crop protection.