Setup for Post-Emergence Herbicides

Bill Johnson: We’re in a section of the field now that has been treated with a low rate of a pre-emerge herbicide. Sometimes we call these setup herbicides, Roundup Ready or Liberty Link setup herbicides. Essentially what we do with that strategy is we apply about one-half to two-thirds of the normal recommended rate to these fields in an effort to keep early season weed emergence at a minimum and yet allow us to reduce our costs and put our post-emerge treatments on in an effective manner.
In this area right here most of the weeds are anywhere from about one- to three-inches tall. This is a stage when weeds can be very effectively controlled by post-emerge herbicides and we have minimal worries about weeds escaping post-emerge herbicides provided they’re labeled to control them. The weeds that we have remaining here with this reduced rate of a pre-emerge herbicide are a few giant ragweed, a few velvet leaf, some pigweeds and some Jimson weeds, morning glories, weeds that will commonly escape reduced rates of soil-applied herbicide.
One of the things that we would recommend in the eastern Corn Belt when you put on a post-emerge herbicide is to add a residual herbicide with it in hopes of reducing the amount of late-season weed reemergence after you kill these weeds. That’s a pretty effective strategy to minimize seed production and especially minimize seed production from weeds that have a long germination pattern, like giant ragweed, morning glory, water hemp, burnt cucumber, and some of those.