Is the current state of the art of weed monitoring suitable for site-specific weed management in arable crops?

Weed monitoring is the first step in any site-specific weed management programme. A relatively large variety of platforms, cameras, sensors and image analysis procedures are available to detect and map weed presence/abundance at various times and spatial scales. Remote sensing from satellites or aircraft can provide accurate weed maps when the images are obtained at late weed phenological stages. Cameras located on unmanned aerial vehicles (UAVs) have been shown to be adequate for early-season weed detection in a variety of wide-row crops, providing images with relatively high spatial resolutions. Alternatively, weed detection/ mapping systems from ground-based platforms can achieve even higher resolutions using a variety of nonimaging and imaging technologies. These ground systems are suited, in some cases, for real-time site-specific weed management. Despite this rich arsenal of technologies, their commercial adoption is, apparently, low. In this study, we describe the state of the art of remotely sensed and ground-based weed monitoring in arable crops and the current level of adoption of these technologies, exploring major constraints for adoption and trying to identify research gaps and bottlenecks.