Most of the corn and soybean acres have emerged, and with the recent rains and heat the crops are growing very fast and beginning to look pretty good. Unfortunately, the crops are not the only vegetation taking advantage of the moisture and heat. The broadleaf and grass weeds are flourishing, as well! Since most of the post emergent herbicide labels cover weeds up to 6 inches in height, a decision to make a post emerge herbicide application has to be made very quickly. After review of some pictures from Kirt Watson with Bayer, we can see that giving the weeds the finger can help determine if the weeds are within proper label height limitations and whether they will be controlled.
When you combine the height limitations of our herbicides along with the fact that some of these tough to control weeds such as; palmer amaranth, tall water hemp, and kochia have the ability to grow nearly 1 inch per day under the right weather and soil conditions means the decision to apply a post herbicide has to be made very quickly. Since we have had a significant amount of moisture and high heat, this creates the possibility that a weed could go from 2” and being on label, to greater than 6” and off label in less than a week. Contact any of our Agricultural Services, Inc. agronomy team members to get your post herbicide applications made in a timely manner.