The efficacy of herbicides is influenced by several factors affecting the absorption and translocation of these compounds in the plant. Herbicide plant absorption, for example, is both physically and biologically influenced by temperature and air relative humidity in the plant canopy. With the reduction in relative air humidity and/or increase in temperature, the spray droplets dry more rapidly and the absorption of the herbicide decreases or even stops, affecting the biological performance. Based on that, this research aimed to study the influence of dew and spray volume on the efficacy of glyphosate rates in the control of B. plantaginea. There were significant interactions among volume of water, dew and rate of glyphosate. The lower the water volume, the more effective the glyphosate activity was, especially when applied at the lowest tested rate (90 g ha-1). The presence of dew on the leaves caused reductions in the activity of the product, mainly when the lowest rate was combined with the highest water volume.
herbicides; absorption; rates; water volume
