Cool weather slows weed control; spray when warm
Weed control concerns increase when cover crops were grown on cropland over winter. Cool weather increases risk of failed control. Those beneficial plants become weeds in the next crop.
"If you realize you must spray in cool weather, you may want to increase the rate of glyphosate or whatever burndown herbicide you use."
To improve control, add at least one other tank-mix partner to ensure better success.
Even with low overnight temperatures in the forecast, apply at the time of peak warmth and sunshine in the afternoon. That is when best growth and translocation occur. Avoid early mornings and later afternoons.
"Realize you are not the only one," Bradley says. "I get lots of calls about when to spray in this cool weather."
Spring 2014 provides another learning experience in weed control.
Bradley writes on weeds in the weekly MU Integrated Pest and Crop Management newsletter at http://ipm.missouri.edu/ipcm.