Carey Minteer, University of Arkansas, Bugwood.org
Orchardgrass spring burndown hints
As always, fall applications of glyphosate are much better than spring applications for orchardgrass sod burndown. For those who want to control orchardgrass (or quackgrass) in the spring here are a few considerations:
- Wait until orchardgrass is 6 to 10 inches tall and actively growing.
- Use at least 1.13 lbs ae/acre or higher glyphosate (this would equal 32 fl oz/A Roundup PowerMax or 48 fl oz/A of a "generic, 3L" glyphosate product).
- In some cases, up to 3 qt/A glyphosate may be necessary to provide effective control, especially if tank-mixing with atrazine or other clay-based herbicides due to antagonism.
- Many pre-residual herbicides can be included in the spray mixture as well; products listed as "preplant" can be applied at this point; Prowl or pendimethalin products should not be applied if corn has not yet been planted.
Spring seeded forage weed control considerations
For those of you who have planted or will soon plant forages (alfalfa and/or grass) here are a few options to consider for weed management.
- Herbicide options for alfalfa only:
- Broadleaf weeds: 2,4-DB and Buctril
- Grass weeds: Poast (Plus) and Select (clethodim)
- Broadleaf and grass weeds: Pursuit and Raptor; Gramoxone can be used between cuttings
- Glyphosate-containing products can only be broadcast applied in Roundup Ready alfalfa varieties; otherwise only up to 10% of the field can be spot-sprayed
- Make sure to consider crop maturity before applying; most of these herbicides require alfalfa to have at least 2 to 4 trifoliates
- There are no herbicides that can be applied in seedling alfalfa/grass mixtures; only metribuzin and Pursuit can be applied to established stands
- Control weeds as early as possible when they are actively growing and are 1 to 3 inches tall
- Broadleaf herbicide options for use in seedling grass forages:
- 2,4-D, Clarity/Banvel, Crossbow, ForeFront, Cimarron Plus, metsulfuron products, Stinger, and Yukon
- As a general rule of thumb: do not apply growth regulator products (2,4-D, dicamba, etc.) until forage grasses are well established; this usually occurs when they are 4 to 5 inches tall or 45 to 60 days after planting
- For the ALS products such as Cimarron and metsulfuron it is best to wait 6 months before application in orchardgrass, brome, and bluegrass; 12 months for timothy, and 24 months for fescue