Early Burndown In Corn

JACKSON, TENN.

 Early Burndown. One overall observation on the winter annual weed pressure this spring is that bluegrass and henbit pressure is extremely heavy across many Tennessee row crop fields. In general, horseweed pressure appears to be less than it was this time last year.

   There have been some burndown applications going out recently for intended corn ground. One new burndown tankmix that is going out is 0.75 lbs of glyphosate + 10 oz/A of Verdict + 1 oz/A of Resolve. This burndown tankmix performed well for me, but I only had it in one study. It provided good control of horseweed and most other existing winter annuals. It should also often provide residual horseweed control up to corn planting time. This tankmix is very flexible as corn, soybean and cotton may be planted after this application. Of course the other very popular tankmix in early March that is extremely flexible is 0.75 lbs of glyphosate + 8 oz/A of Clarity mixed with 1.5 to 2 oz/A of Valor. Either one of these tankmixtures will often provide residual up to planting time. However, if planting is delayed this might not be the case. In that situation, 1qt of atrazine plus 1% COC at planting could burndown any newly emerged weeds. However, under heavy weed pressure, Gramoxone Inteon may need to be tankmixed with the atrazine.

   After the burndown and some kind of PRE application, the most important herbicide application needs to be considered. This main herbicide application for corn needs to be applied early POST. Regardless of whether you are using Halex GT, Degree Extra, Bicep, Capreno, or just more atrazine + glyphosate they work best applied from V1 to V3. Applied early POST will provide the most consistent in-season control. Δ

DR. LARRY STECKEL: Extension Weed Specialist, University of Tennessee