Weed Control Guide for Ohio Field Crops

Corn: Soil-Applied Herbicides Preplant or Preemergence

Herbicide	Formulation	Product Rate Range
AAtrex/Atrazine	4L	2 - 4 pt
	90DF	1.1 - 2.2 lb

Tank-mix with: Most preplant and preemergence corn herbicides.

• Mode of action: photosynthesis inhibitor.
• Atrazine is generally applied at a rate of 1.4 to 2 pounds active ingredient per acre to control broadleaf weeds. Higher rates will also provide grass control, but may cause injury to subsequent crops in the rotation.
• Low rates may result in reduced control of velvetleaf, cocklebur, giant ragweed, and morningglory. Rates approaching 2 pounds active ingredient may be necessary for velvetleaf control, but will also increase carryover risk. Atrazine will not control fall panicum, regardless of rate.
• Maximum soil-applied rate on soils not highly erodible is 2 pounds of active ingredient per acre. Maximum rate on highly erodible soils is 2 pounds active ingredient on fields with at least 30% crop residue, and 1.6 pounds active ingredient on fields with less than 30% crop residue. Soil applications may be followed with a postemergence application of atrazine, but total of all treatments cannot exceed 2.5 pounds active ingredient per acre per year.
• Do not mix, load, or apply within 50 feet of wells. Do not mix or load within 50 feet of intermittent streams and rivers or natural or impounded lakes and reservoirs.
• Do not apply within 200 feet of natural or impounded lakes and reservoirs. Do not apply within 66 feet of the point where field surface water runoff enters perennial or intermittent streams and rivers. If applied to highly erodible land, the 66-foot buffer between treated areas and runoff entry points must be planted to crop or seeded with grass or other suitable cover.
• Preplant applications of atrazine or atrazine plus Bladex can provide burndown of small, emerged annual weeds. Control is improved when applied with crop oil and/or liquid fertilizer solution.
• Plant only corn or sorghum the year (including fall) of atrazine application.
• Where soybeans will be planted the following spring, do not apply more than 1.6 pounds active ingredient per acre.
• Where oats, forage legumes, or forage grasses will be planted the following spring, do not apply more than 0.8 pounds active ingredient per acre.
• If atrazine is applied after June 10, plant only corn or sorghum the following year.
• Do not plant sugar beets, tobacco, or vegetable crops the year following application.
• Risk of carryover is greater after a cool, dry season and on soils with pH greater than 7.3.

Back | Forward | Table of Contents