Spring drought can provide an advantage for weeds in alfalfa especially in newly seeded fields. Usually, glyphosate applications sprayed on Roundup Ready® alfalfa variety fields can be effective overcoming these emerged weed issues; but Roundup® isn’t the only good weed control option for alfalfa.
When weeds grow faster than stressed alfalfa, seedlings are robbed of moisture, nutrients, and light. Left uncontrolled; weeds can then thin stands, weaken plants, and lower yields. For broadleaf weeds, mowing may be an option while the alfalfa is growing slowly. Adjust mowing height so several leaves remain on the alfalfa seedlings after clipping to aid in alfalfa regrowth. However, if mower clippings would smother young alfalfa seedlings; then alternative herbicide may still be your best weed control options if Roundup® is not an option.
Nebraska Extension 2022 “Guide for Weeds, Disease and Insect” publication EC-130 Provides comparison of response ratings for many labelled herbicides. Alfalfa seedling post-emergent herbicides may include: AIM®; Moxy 2E®; Poast®; Buctril®; Raptor®; Select Max®; Prowl H²O®; Warrant®; Pursuit®; Arrow® and Butyrac 200®.
For established alfalfa, labelled broadleaf or grassy weed herbicides include: Aim®; Moxy 2E®; Butytrac®; Chateau®; Gramoxone®; Karmex®; Metribuzin®; Prowl H²O®; MCPA Amine®; Arrow®; Warrant®; and Velpar®. These products are most effective when applied before weeds reach 4 inches tall.
As always, read and follow label directions for application rates and conditions.
By Todd Whitney
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