Pub of the Month: Conversion of Toxic tall fescue to novel endophyte tall fescue

Successful conversion from toxic KY-31 to novel endophyte tall fescue begins much earlier than most people anticipate. Seedheads need to be clipped before maturation, the existing stand needs to be sprayed out in July/August and reseeding needs to be in early September. Check out this simple checklist below for how to make the transition this summer and fall.

Conversion of Toxic Tall Fescue to Novel Endophyte Tall fescue

S. Ray Smith and Krista Lea – University of Kentucky

Replacement Protocol:


Soil sample; adhere to lime and fertilizer recommendations

  1. Take soil sample in May.
  2. Follow recommendations in soil test.

Remove/prevent all tall fescue seed heads in the spring via mowing or early hay cutting

  1. Clip/mow the pasture in early May as low as possible. 
  2. Clip/mow the pasture a second time in late May to remove tall fescue seed heads (Note: Fescue seed can be viable 15-20 days after pollination and then germinate in the fall).

Mid-Late Summer

Herbicide spray to kill out existing stand before planting novel endophyte tall fescue or other forages

  1. Graze tall fescue heavily during periods of growth.
  2. Stop grazing and allow tall fescue to regrow to five to six inches in height.
  3. Spray with glyphosate 4-6 weeks before planting – mid to late-July.
  4. Allow weeds and toxic tall fescue to germinate or re-grow from escapes.
  5. Re-spray glyphosate before planting – early September


Plant novel endophyte tall fescue seed

  1. In early to mid-September, just after last weed spray, plant a novel tall fescue variety using a no-till seed drill.
  2. No-till drill at 20 lbs/ac, and ¼ inch deep. To achieve better ground cover, set drill at 10 lbs/ac and go over field twice, the second pass perpendicular to the first pass.

Late Fall or early next Spring

Tall fescue seedling management

  1. Low rates of N can be used to enhance stand establishment (~40 lbs/N/ac)
  2. After planting, wait until tall fescue seedlings reach the 4-leaf stage (4 to 5 inches tall) before weed control.
  3. If needed, apply Weedmaster (2,4-D and dicamba) or similar herbicide to control broadleaf weeds. 
  4. Allow good sod development before grazing next spring. Ideally, wait until plants are 8 inches tall and flash graze (a large number of animals for half a day) or mow at 4 inches residual height or simply cut for hay in the spring (4 inch stubble height).