Mark VanGessel, Extension Weed Specialist; mjv@udel.edu
Be sure to scout your planted fields to determine if and when a postemergence treatment is necessary. Under good conditions, postemergence treatments are typically needed four to five weeks after the preemergence herbicides were applied. That is based on when the herbicides were applied, not when the crop was planted. Also, if reduced herbicide rates were used or the herbicide did not get activated, this time frame maybe less than four weeks. Also, if are relying on someone else to spray your fields, they may not be able to get to your fields right away, so be sure to budget time for the sprayers to respond (and with the spring we have been having the sprayers are probably behind). This is extremely critical if you have Palmer amaranth in your fields. Plan ahead, because if you let the weeds get too tall, you may not have any backup options.