Control Weeds In Full Season Beans

Posted: July 22, 2015

It is getting to the point in the season where we hopefully have controlled our weeds in full season soybeans. Soybeans have moved into the reproductive phase with flowering in full swing in many areas, which is often the tail end of when soybean herbicides can be applied.

Extension Agronomist Bill Curran reminds us the application of herbicides during pod set can have the potential to reduce pod numbers, so consider this before making an application. Some herbicides simply have a “days to harvest” restriction which is based on tolerable residue amounts that may enter the grain. In addition, most of the weeds are getting big, so the effectiveness of the herbicide will be greatly reduced.

Glyphosate (Group 9) and ALS-resistant (Group 2) weeds are a particular concern because these will generally require a contact or PPO (Group 14) product. The PPO or contact products will burn and stunt the soybeans, so later season applications can potentially reduce yield.

(Contributed by Leon J. Ressler, District 17 Director as part of his Now Is The Time column for July 18, 2015.)