Missouri Department of Conservation

Guidelines for Converting Tall Fescue to Other Forages or Herbaceous Cover

Fall Applications

Glyphosate (ROUNDUP) or Sulfosate (TOUCHDOWN 5) applied in the fall will control 95 percent of tall fescue. Re-infestation will occur from seed unless seed heads were mowed in mid-May or early June before maturity.

• Mow, hay or burn in July or August to reduce residue and ensure maximum exposure of new growth to herbicide contact.
• Apply 1 qt./ac. glyphosate or 0.8 qt./ac. sulfosate, plus 6 to 7 oz. non-ionic surfactant in 10 to 20 gal. water/ac. and 17 lb. ammonium sulfate/l00 gal. solution, between Sept. 1 and Nov. 1 when fescue is 8 to 10 inches tall and actively growing (60 to 70 degrees F).
• Re-treat in April or May with 1 qt./ac. glyphosate or 0.8 qt./ac. sulfosate. There will probably not be adequate growth for treatment before April 1 in the south zone or April 15 in the north. A late winter or early spring burn may produce earlier growth.
• Plant with no-till drill in moderate residue (never plant in heavy fescue residue). A standard grassland drill or air spreader may be used in light residue, or if residue is burned prior to seeding. Cultipack or tread with cattle after seeding with an air spreader. For tilled seed beds, wait seven to 14 days after the last herbicide application before disking.
• Late spring (April 15-May 15) seeding of cool-season grass (CSG)/legumes is possible if all goes well. Native warm-season grasses (NWSG)/forbs should be seeded as early as possible to allow weather to heal cuts from residue coulters on most no-till drills. Drills with trash plows (Truaxflex-drills) and standard drills do not leave deep cuts so planting may be later.
• If seeding can’t be completed before the deadline or because seed is not available, plant a summer smother-crop such as sorghum, Sudan grass or pearl millet for better fescue control or erosion protection. CSG/legume can be planted in the fall; NWSG/forbs in the dormant period or the following spring, leaving the cover crop mulch for protection.
• Burn after the second growing season or after the first if no winter-heaving is evident.

Imazapic* (PLATEAU) is labeled for controlling tall fescue at 12 oz./ac./yr, but may only be used at 4 oz./ac./yr. on CRP land. Thus imazapic by itself should not be used on CRP to convert tall fescue. It may be used at the higher rates on EQIP land and land that is not grazed or hayed. (A change in grazing restriction is expected by February 2001.) Annual weed control will be less than if used in the spring. The only advantage of using imazapic in the fall is to reduce adverse effects on side-oats grama, eastern gama grass, and susceptible native forbs, e.g. compass plant and ashy sunflower.

• Mow, hay or burn in July or August to reduce residue and ensure maximum exposure of new growth to herbicide contact.
• Apply 12 oz. imazapic + 2 pints of methylated seed oil (MSO) per acre.
• Plant nwsg and native forbs during the dormant period or following spring.

Glyphosate or sulfosate + Imazapic will give more consistent control of tall fescue than either product alone and will allow using a lower imazapic rate for sensitive forbs and nwsgs and for CRP land. Annual weed control will be less than if imazapic is used in the spring.

• Apply qt./ac. glyphosate or .8 qt./ac. sulfosate plus surfactant in the fall as described in step 1 a and b.
• Burn residue in the spring and apply 4-8 oz./ac. imazapic (use no more than 4 oz./ac. on CRP) and 2 pt./ac. MSO in 20 gal. of water/ac. a few days before or after planting. (Omit MSO if nwsg or forb seedlings have emerged.)
• Switchgrass, eastern gama grass, side-oats grama and several native forbs may be stunted or killed by imazapic, especially at the higher application rates. Increase the seeding rate in mixtures that contain these species to allow for some plant loss.

Gramoxone (Paraquat), in split applications, has provided 65- to 85-percent control of intensively grazed or hayed tall fescue. alt has been less tested on idle tall fescue such as CRP. Gramoxone should only be applied by a properly trained, equipped and attired commercial applicator.

• Apply 2.5 pt. gramoxone in 20 to 30 gal. water/ac. in early fall when fescue is actively growing.
• Wait 10-21 days for regrowth and apply 1.5 pt. gramoxone in 20 to 30 gal. water/ac.
• Plant CSG/legume before the fall deadline or nwsg/forbs during the winter dormant period or following spring, OR

• Plant a winter smother-crop, barley or wheat, kill in the spring with 1.5 pt/. gramoxone, and plant csg/legumes or NWSG/forbs during the respective spring seeding period.

Spring Applications

Glyphosate or Sulfosate applied in the spring will give 50- to 90-percent tall fescue control, but seedling recruitment, escapes, and skips are problems with spring treatment without a second application.

• Mow or burn residue in winter to encourage new growth.
• Apply 2 qt./ac. glyphosate or 1.6 qt./ac. sulfosate, plus 6-7 oz. nonionic surfactant in IO to 20 gal. water/ac. and 17 lb. ammonium sulphate/100 gal. of solution, when most plants have reached the boot to early seed head stage.
• If a clean-tilled seedbed is planned, wait seven to 14 days before disking. For no-till, wait two to three weeks after a second, 1 qt./ac. glyphosate or .8 qt./ac. sulfosate application, for herbicides to breakdown before seeding.
• Late spring seeding of CSG/legume may not be possible but there should be time to plant nwsg/forbs.
• If CSG/legume or nwsg/forbs cannot be planted, plant a summer smother-crop. Mow to 8 to10 inches in August and apply 1 qt./ac. glyphosate or .8 qt./ac. sulfosate within a few weeks to cleanup residual fescue. CSG/legume can be planted in the fall; nwsg/forbs during the dormant period or the following spring, leaving the cover crop mulch for protection.

Imazapic

• For non-CRP acreage, apply 12 oz. imazapic + 2 pints of MSO per acre after fescue greenup but before boot stage.
• Burning fescue residue before herbicide application will enhance herbicide effectiveness and aid fescue control.

Glyphosate or Sulfosate +Imazapic gives better fescue control than either herbicide by itself plus annual grass control, eliminating the need for weed-control mowings. It is the most efficient and cost effective method.

• Apply 1 to 2 qt./ac. glyphosate or .8 to 1.6 qt./ac. sulfosate, plus 6 to 7 oz./ac. nonionic surfactant, in IO to 20 gal. water/ac. and 17 lb. ammonium sulfate/100 gal. of solution when tall fescue is 8 to 10 inches tall.
• Wait seven to 14 days, bum killed residue, plant nswg mixture and apply 4 to 8 oz./ac. imazapic (use only 4 oz./ac. on CRP land),

Gramoxone, in split applications has given 65- to 85-percent control of heavily grazed tall fescue. Results on idle fescue such as CRP may be different. a. Apply 2.5 pt. gramoxone in 20 to 30 gal. water/ac.

• Walt IO to 21 days for regrowth, and apply 1.5 pt. gramoxone in 20 to 30 gal. water/ac.
• Plant csg/legume or nwsg/forbs during the respective spring periods, or plant a summer smother-crop for greater fescue control and plant csg/legumes in the fall or nwsg/forbs during the winter dormant period or following spring.

Clethodim (Select) split applied at 10 to 12 oz./ac. similar to Gramoxone, has given 85 to 95 percent control of tall fescue on non-cropland. Check label recommendations.

Glyphosate or Sulfosate plus Gramoxone, split applied, has given adequate control.

• Apply 2 qt./ac. glyphosate or 1.6 oz. sulfosate, as described in Spring Applications, step 1.
• Wait 21 to 28 days and apply 1.5 pt./. gramoxone or 1.5 to 2 pt./. glyphosate or 1.2 tol.6 pt./ac. sulfosate.

Cropping is the least costly method if time is not critical and soils are tillable because crop income can offset fescue eradication costs. This may not be applicable for assistance programs like CRP.

• Apply 1 qt. glyphosate/. or.8 qt./ac. sulfosate in the fall or 2 qt./ac. glyphosate or 1.6 qt./ac. sulfosate in the spring as described above.
• Plant a summer crop of milo or soybeans with weed control herbicides. Do not use imazaquin herbicides (SCEPTER, STEEL, SQUADRON, or TRISCEPT) with soybeans due to carryover that can affect nwsg establishment.

Always read and follow labels when using pesticides. Pay attention to grazing and/or haying restrictions following herbicide application.