| Abstract: | The influence of volume rate and nozzle size on the activity of difenzoquat and glyphosate against outdoor, pot-grown wild oats and barley plants, respectively, was assessed using a parallel-line assay technique. The results showed that the assumption of parallel dose-response curves for difenzoquat and glyphosate was not rejected in either experiment. An inverse relationship between herbicidal activity and volume rate was found with both herbicides, but volume rate had a more pronounced impact on glyphosate activity than on difenzoquat activity. For a given spray volume, no impact of nozzle size on the activity of glyphosate was found. The advantages of applying the parallelline assay in studies of the influence on herbicide activity of factors not supposed to affect the mode of action of the herbicide are discussed. |
