Remote sensing technology is critical for plant health assessment to aid in precision application and management programs. For solving different problems, various scales and bands of sensors are needed. We developed color-infrared (CIR) and thermal infrared (TIR) imaging systems for both airborne piloted and unmanned aircraft, and visible near-infrared (VNIR) hyperspectral imaging systems for ground-based and laboratory-scale operations. Using Color-Infrared (CIR) and thermal infrared imaging (TIR), we mapped crop injury induced by off-target drift from applied herbicides and assessed crop canopy temperature as it relates to crop water stress. With VNIR hyperspectral imaging systems, we characterized the subtle changes in crop spectrum to identify the onset of crop stress caused by factors such as herbicide damage, water deficit, and nitrogen deficiency. This allows crop stress to be detected early before symptoms become visible so appropriate actions for timely remediation can be taken. With the adoption of herbicide-resistant (HR) crops, repeated and intensive use of herbicide has exerted high selection pressure on weed populations, resulting in the evolution of HR weeds. Identification of HR weed species and populations in a crop field is important in practice, but the identification process is tedious and labor-intensive. Alternatively, sensitive optical remote sensing could provide a rapid, non-intrusive way to differentiate HR weeds from herbicide-sensitive (HS) weeds.

 

We demonstrate the systems and application of the systems, including aerial CIR mapping of crop injury from glyphosate, aerial TIR mapping for crop stress management, laboratory VNIR imaging for early detection crop injury from glyphosate, and field VNIR imaging for differentiation of GR and GS weed species. New low cost unmanned aerial systems for rapid plant health assessment are also described. Limitations for application of the systems are also discussed.