Our run of nice fall weather has contributed to an earlier harvest season and is providing a window of opportunity to apply herbicides for fall weed control. As long as we are getting temperatures above 50F fall weed control can be very effective. From an agronomic standpoint fall weed control is often stressed as a crucial step in controlling marestail in fields that will be planted to soybeans. Variability of marestail control with spring-applied 2,4-D/glyphosate has become a major problem in the state, primarily in fields not treated the previous fall or those not treated until sometime in May.
In addition to marestail control, fall is still the key time to control tough biennials and cool-season perennials such as wild carrot, poison hemlock, and dandelion. Spring/summer treatments of 2,4-D or dicamba won’t necessarily be as effective as a fall treatment. For those fields that have a history of problematic infestation of winter annuals such as henbit and purple deadnettle, fall is the time to apply herbicides for control.
Since we never know what spring will bring in terms of opportunity for timely herbicide application, take advantage of this fall’s weather to get a jump on 2016 weed control.