Weed Control Guide for Ohio Field Crops

Burndown Herbicides in No-Tillage Corn and Soybeans

Herbicide	Formulation	Product Rate Range
Roundup Ultra Max	3.75SL	13 - 52 oz
Roundup Ultra Dry	65DF	10 - 38 oz
Roundup Custom	4L	12 - 48 oz
Roundup Original	3L	12 - 64 oz
Glyphomax, Glyphomax Plus	3L	12 - 48 oz
Touchdown	3L	16 - 64 oz
Cornerstone	3L	16 - 64 oz

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

• Do not apply broadcast after the crop has emerged, unless the crop has tolerance to glyphosate and is labeled as Roundup Ready. Some of the products shown may not be labeled for postemergence use on Roundup Ready corn.
• All of the products shown contain glyphosate, a nonselective, translocated herbicide that controls emerged annual and perennial grass and broadleaf weeds, volunteer cereals, and grass cover crops. Products with the trade names Glyphosate, Glyphosate Original, Glyfos, and Glyfos X-Tra are similar to those listed above. Application rates, adjuvant recommendations, application parameters, and other guidelines for use vary among glyphosate products, and users should consult labels and local product use guides for more specific information. The following comments are meant as general guidelines for the use of glyphosate.
• Mode of action: EPSP synthase inhibitor.
• Most annual weeds can be controlled with the lower labeled rates when less than about 6 inches tall. Rates should be increased accordingly as weeds become taller. Pennsylvania smartweed, atriplex, giant ragweed, crabgrass, fall panicum, barnyardgrass, and a number of winter annual weeds can be difficult to control, and should be as small as possible at the time of application. A mixture of glyphosate plus 2,4-D ester (1 pint/A) will improve control of prickly lettuce, dandelion, marestail, giant and common ragweed, Pennsylvania smartweed, velvetleaf, mustard species, and other broadleaf weeds.
• For control of rye or overwintered wheat, apply in a spray volume of 10 gpa or less and use the appropriate rate for small grain size. Wheat should be treated before reaching a height of 18 inches.
• Roundup and Glyphomax products can be applied immediately prior to alfalfa harvest in spring or fall, and the treated alfalfa and weeds harvested and fed to livestock. This application is useful where corn will be planted immediately after alfalfa harvest, since it provides more effective alfalfa and perennial grass control, compared to application after harvest. Allow a minimum of 36 hours between application and harvest. Alfalfa should be harvested 3 to 7 days after application to avoid loss of quality and maximize perennial control. The preemergence herbicide program for corn should include atrazine at a rate of 1 1/4 to 1 1/2 quarts (or the equivalent amount in a premix). Postemergence application of Banvel or Banvel + 2,4-D may be required for complete control of alfalfa in the corn.
• Glyphosate activity will be maximized when applied in water in a spray volume of 10 gpa or less. When tank-mixing with residual herbicides, apply in 10 or more gallons of water or nitrogen fertilizer solution per acre.
• Glyphosate activity on perennial and large annual weeds may be reduced when mixing with residual herbicides or applying in nitrogen fertilizer solution. Residual herbicides most likely to reduce activity include Bullet, Partner, MicroTech, and herbicides with contact activity on emerged weeds (Sencor, Domain, and atrazine). Consult labels for rates and precautions when tank-mixing with residual herbicides.
• Recommendations for the use of ammonium sulfate (17 lbs/100 gallons of water) with glyphosate vary among products. Addition of ammonium sulfate may improve control, and is recommended under the following conditions: when tank-mixing with residual corn or soybean herbicides, when air temperature is 55 degrees or less, or when hard or high pH water is used as the carrier.

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