Alleviating Environmental Impacts on Herbicide Performance.
The opportunity to reduce the negative impacts of moisture stress on herbicide performance is very limited. Several research studies suggest that alleviating environmental impacts depends on the level and duration of moisture stress. Plants exposed to mild moisture stress have been controlled by increasing herbicide rate or alleviating moisture stress within 48 hr of herbicide application (Rossi et al. 1994). Plants growing under moderate moisture stress may require both increased herbicide rate and alleviation of moisture stress within 48 hr of application. Plants experiencing severe moisture stress at the time of application will not respond favorably even if the herbicide rate is increased and moisture stress is alleviated within 48 hr of application. While this information was generated to understand the effects of Whip (fenoxprop) on moisture stressed green foxtail and crabgrass, the concept applies to many other herbicides.