Weeds have been slow to start off

By Harold Watters

With high winds, frequent rains and late snows we missed proper burndown timing, pre-emergent herbicide application and now are working on missing the proper timing for post applications. Consider adding a second component to that glyphosate application when you do post your corn or soybeans. The idea is to have a second method of attack on those weeds that may be resistant, have grown a little larger than planned or you have had problems with in the past. Yes, I know dicamba beans are now available, but that product works best in a pre-emergent situation for Ohio.

The Ohio, Indiana & Illinois Weed Control Guide is a great resource for getting management tips on how best to apply glyphosate. Also see the corn tables and the soybean tables to choose potential partners for post applications. The Guide is available free on-line from Mark Loux on his Weed Management website: https://u.osu.edu/osuweeds/.

Don’t forget about drift. The spring burndown season was more than a little scary, and hopefully we will be into post spray season soon, so there is still potential for drift onto sensitive crops. Here from the Weed Control Guide are some tips on how to reduce the chances for drift.


Off-target movement of herbicides

Spray drift is the downwind movement of spray particles from the application site to non-target areas, some with sensitive plant species. The extent of spray drift increases as:

(1) the size of spray droplets decreases,

(2) the height above the ground from which the droplets are released increases, and

(3) wind speed increases.


Drift can be minimized by following these guidelines.

  • Spray when wind speed is low.
  • Use the maximum nozzle orifice size without distorting spray pattern.
  • Reduce spray pressure to the lowest setting without distorting spray pattern.
  • Using nozzles that minimize drift, such as Air Induction, Turbo Teejet, or Flat Fan DriftGuard nozzles.
  • Use drift control agents when permitted by the label.
  • Follow label precautions for drift reduction measures.


Harold Watters, Extension Field Agronomist, works out of the Extension office in Bellefontaine and can be reached at watters.35@osu.edu or by phone at 937 599-4227.

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