Herbicide weed control on pavements: Advances in application technology

Summary

In 2008 and 2009 we tested 11 machines from three categories of herbicide application technology: weed wipers, controlled droplet applicators (CDA) and sensor sprayers. Machines were tested on amount of glyphosate use and efficacy of weed control on three types of pavements typical for weed control in urban area. Test plots were over 100 m2; sufficiently large to do representative measurements. Weed wipers used the least amount of herbicide, less than 0.05 L product ha-1. Sensor sprayers applied between 0.1 and 0.4 L product ha-1 depending on weed infestation level, and configuration of the machine. Double the amount of nozzles and sensors on the spray boom reduced herbicide use by about 50%. CDA machines were set to 0.9 to 1 L product ha-1 with good efficacy. CDA combined with a sensor gave 40% reduction in herbicide use in one trial. CDA machines had smaller ED90 (effective dose 90% control) values then the sensor sprayers. This confirms that glyphosate application in small and uniform droplets with less water are more effective. All machines tested complied with the dose cap of the SWEEP system, which is important for achieving sustainable weed control on pavements.