Dicamba, Liberty and atrazine are the most effective options for controlling marestail post-emergence in corn, and atrazine alone may not kill larger plants.

From visiting with retailers the past month it is very apparent there will be a major shortage of dicamba for burndown again this spring. A number of folks from different retailers have stated that they have been allocated only a fraction of all the dicamba they sold two years ago.

Dicamba is a growth regulator herbicide that can be used to control existing weed vegetation prior to crop planting.

There is still time this fall to apply herbicides for control of winter annuals and marestail.

The list of herbicide active ingredients available for pre-harvest applications in corn or soybeans is relatively short, says University of Illinois Extension weed specialist Aaron Hager.

A successful weed control program for fallow fields may still be a needed to keep weed pressure down and reduce the introduction of more weed seed into the soil seed bank which can impact future crops.