AERIAL-PHOTOGRAPHY AND VIDEOGRAPHY FOR DETECTING AND MAPPING DICAMBA INJURY PATTERNS

Field trials were conducted to compare on-site visual evaluations with color-infrared photography (CIR), and near-infrared (NIR) videography (video) and hand-held radiometry (HHR) for detecting and mapping dicamba injury in cotton. CIR, video, and HHR detected 48%, 42% and 36%, respectively, of the injured crop area as defined by visual evaluation (injury ratings > 0 on a scale of 0 to 9). The remote techniques were unable to differentiate crop injury that did not involve the entire plant canopy. Reflectance measurements in the visible red (R) (630-690 nm) and NIR (760-900 nm) wavelengths were taken and used in herbicide dosage prediction equations. Predicted herbicide dosages were significantly, positively correlated (P less-than-or-equal-to 0.01) with physical measures of herbicide present. These studies suggest that remote detection and mapping of moderate and severe herbicide injury is possible. Further, NIR videography, with near-real-time capability and low cost may be the system of choice for this type of application.