Abstract: The influence of three simulated dew levels and 150, 300, and 450 L/ha spray volume on glyphosate control of oat plants was determined from pot experiments. Results showed that the effect of dew level on glyphosate efficacy was related to application volume. Glyphosate efficacy at the low and medium application volume (150 and 300 L/ha) was not affected by dew level. However, glyphosate efficacy decreased when applied at the high spray volume (450 L/ha), regardless of dew level. However, high dew level reduced efficacy only when glyphosate was applied at 450 L/ha.

Nomenclature: Glyphosate; oat, Avena sativa L.

Additional index words: Application volume, glyphosate activity, foliage water retention, foliage free water.

Abbreviations: DAE, days after emergence; HDA, homogeneous dew area.