Glyphosate-resistant horseweed populations have become more widespread in the state and are now a significant management issue in western PA and the Northern Tier. In addition to glyphosate- or glyphosate and ALS-inhibitor resistance, horseweed is challenging to control because of variable emergence patterns.

As we proceed through the growing season, there are several issues surrounding weed control and herbicide use in corn, soybean and small grain fields.