Real-time Application of Herbicides in Seed Lines by Computer Vision and Micro-Spray System

Droplet application of herbicides at single weed seedlings was studied. Manual application of the droplets showed that 1 µg per plant gave 95% efficacy. Assuming a weed density of 100 plants m-2 this result corresponds to a glyphosate consumption of only 1 g ha-1. Automatic application of herbicide droplets was performed with a vision controlled micro-spray system installed in an autonomous robot. Under indoor conditions it was demonstrated that objects which were the size of a weed seedling could be hit at sub-centimeter accuracy. Only about 10 µL of spray liquid was used per object which corresponds to a few µg of glyphosate. In an outdoor field experiment with the automatic micro-spray system efficacies of 82% were obtained with 22.6 µg of glyphosate per plant on average. This is only around 4% of the official label recommendation for glyphosate.