Cogongrass Eradication Planning

This page is a collection of advice and links that appear to pertain to the infestation of Cogongrass in the north fields.

Cogongrass Control Recommendations from CogonGrass.org

  • Small Area – Treat larger infestations with glyphosate using a tractor-mounted boom sprayer calibrated to deliver 10 to 15 gallons of spray solution (water + herbicide) per acre. Use glyphosate at the rate of 3 to 4 pounds active ingredient per acre. This translates into 3 to 4 quarts of herbicide per acre for the 41% active material. Replacement species should be planted in the area following the last treatment (either spring or second fall after 90% control is achieved) to suppress reinfestation.
  • Plant crimson clover or ryegrass after the fall application of glyphosate to stabilize sloping areas through winter. Replace this cover crop with a perennial grass or with shrubs planted in a high-density pattern to provide shade over the area.
  • Where selective treatment is not needed, tank mixes of glyphosate (3 to 4 pounds active ingredient per acre) plus imazapyr (Arsenal 1 to 4 pints per acre) are effective.
  • Burning or mowing prior to herbicide application may increase chemical effectiveness by eliminating thatch and causing the production of new growth, which better absorbs pesticide.

From Cogongrass Eradication Stratagies by The Georgia Forestry Commission (GFC).

PINE WOODLANDS: The GFC recommends applying a tank mixture of imaxapyr with glyphosate between May and November to eradicate cogongrass rather than seeking solely to suppress seed production in the spring. This single treatment is more cost effective and has greater first year control. Apply a tank mix of 1-2% Arsenal AC® plus 1-2% glyphosate plus 1% Dynea-pak®; or 2% Chopper Gen2® plus 1-2% glyphosate plus 1% Dyne-a-pak or 2-3% Chopper® plus 2% glyphosate plus1% Dyne-a-pak®. Use 15-25+ gallons of water per acre. Be sure the spray contacts all leaves including the lower layers near the ground line. Spraying to runoff is not necessary, but all areas should be thoroughly covered including a 10 foot (minimum) zone completely surrounding the grass. The roots are often outside the above-ground zone before the above-ground portions of the plant emerge, so spraying outside spots is necessary.

WOODLAND AREAS WITH DESIRABLE HARDWOODS:
Areas with desirable hardwood trees should be treated only with glyphosate products. During the active growing
season (May-November), apply 2% glyphosate plus 1% Dyne-a-pak® in 15-25+ gallons of water per acre. The spray
should contact all above ground leaves including the lower layers. Spraying to runoff is not necessary, but all areas
should be thoroughly covered including the multiple layers of above ground grass. Since soil activity is minimal, it is
absolutely critical to thoroughly cover all above ground portions of cogongrass for best control.

3) RIGHTS-OF-WAY OR OPEN AREAS:
Higher rates of herbicides can be used in these areas; however, the same herbicides and adjuvants may be used.
Chopper® can be applied at rates up to 64 oz. per acre while Arsenal AC® can be applied up to 32 oz. per acre. Burning or mowing prior to herbicide application may increase chemical effectiveness by eliminating thatch and causing the production of new growth, which better absorbs pesticide.

APPLICATION METHODS:
Match the spray equipment to the size of the spot while considering limiting factors such as thick trees, steep terrain
or distribution of the cogongrass on the site. The average site in Georgia is 0.25 acres or less, and the largest site is
over 12 acres. Smaller sites were treated using ATVs equipped with 25-gallon tanks and boomless nozzles or handheld
wands while back-pack-type sprayers were used for the smallest spots. The largest areas were treated by private
contractors using large equipment with long hoses that could treat several hundred feet away from the pump. Subsequent treatments of these larger sites were handled by GFC personnel using backpack or ATV mounted sprayers.


1 Gallon (Fluid) = 256 Tablespoons (Fluid US) = 128 oz.
1% solution per gallon requires 2.56 T = 1.28 oz.
1% solution in the 13 gallon tank requires 16.6 oz. (~1 pint) of product.
chk – 100/13 X 16.6 oz = 128 oz. = 1 gallon of product for 100 gallons of solution.

To treat one acre – Application at 32 oz per acre (see p:3 above) would require 2 tankfuls each with 16.6 oz of arsenal and 16.6 oz of glyphosate.

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