Table 2.6-5. Herbicides for use in established legume forages more than one year old
- See specific product label to determine correct rate for soil type and weed species found in individual fields.
| Herbicide¹ | Application | Product/A | lb ai/A | Crop | Remarks |
|---|---|---|---|---|---|
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| Butyrac 200 2E (2,4-DB) | Postemergence | 1–3 qt | 0.5–1.5 | Alfalfa, birdsfoot trefoil | Apply when weeds are actively growing and no more than 3 inches high or rosettes no more than 2 inches in diameter. Do not apply if temperatures above 90°F or below 40°F are expected during or shortly after application. |
| Chateau 51WDG (flumioxazin) | Dormant or between cuttings | 2–4 oz | 0.064–0.128 | Alfalfa | Apply up to 4 oz to established alfalfa with 6 inches or less of regrowth for preemergence control of certain weeds. Application to alfalfa with greater than 6 inches of regrowth may result in unacceptable crop injury. Do not apply within 25 days of harvest or grazing. Do not apply with any adjuvant or tank-mix with any products formulated as emulsifable concentrates, unless making application following the last cutting of the season. Application with paraquat can be used for winter annuals prior to the winter dormant period. Do not apply to mixed alfalfa-grass stands. |
| Extreme 2.1L (imazethapyr + glyphosate) |
Dormant or postemergence |
2.2-4.4 pt |
0.6-1.2 |
Roundup Ready alfalfa |
Apply over-the-top to Roundup Ready alfalfa varieties only. Apply Extreme when the seedling RR alfalfa is in the second trifoliate stage or larger and when the majority of weeds are 1 to 3 inches (height or rosette diameter). Due to breeding constraints, some alfalfa plants may not contain the glyphosate-resistant gene; thus, some seedlings may not survive the application. A typical application rate of Extreme is 3 pt/A. Allow a minimum of 7 days between treatments. Do not feed, graze or harvest for 30 days after application. If replanting is necessary, do not plant alfalfa for 4 months following an Extreme application. |
| Kerb 50W (pronamide) | Dormant or growing | 1–3 lb | 0.5–1.5 | Alfalfa, birdsfoot trefoil, crownvetch, clovers | Apply in fall or early winter before soil freeze-up. Apply when soil is 55°F or less. Do not use on alfalfa-grass mixtures. (Restricted-use pesticide) |
Metribuzin 75DF |
Dormant |
0.5-1.3 lb |
0.38-1.0 |
Alfalfa and alfalfa-grass mixtures |
Apply in fall after alfalfa goes dormant or in the spring before new growth starts. Alfalfa may be severely injured if new growth is present at spring application. May be applied after dormancy is broken, but before 3 inches of new growth, if impregnated on dry fertilizer. May be used on alfalfa-grass mixtures; higher rates may injure grasses. (Water quality advisory) |
| Poast Plus 1.0 E | Postemergence | 1.5–3.75 pt | 0.19–0.47 | Alfalfa | Apply to actively growing grasses at the size recommended on herbicide label (generally less than 8 inches tall). Always add an oil concentrate or Dash to the spray solution. Nitrogen solution may be added for improved control of certain species. A second application may be needed for complete control of perennial species. May be tank-mixed with 2,4-DB to broaden the weed control spectrum. |
| or | or | ||||
| Poast 1.5E (sethoxydim) | 1.0–2.5 pt | ||||
| Prowl H2O 3.8CS (pendimethalin) | Dormant or between cuttings | 1–4 qt | 0.95–3.8 | Alfalfa | Apply 1.0 to 4.0 quarts to established alfalfa and before weed emergence. Applications can be made in the fall after the last cutting, during winter dormancy, in the spring, or between cuttings. Applications should be made prior to the alfalfa reaching 6 inches in regrowth. Apply 1.0 to 2.0 pints to seedling alfalfa prior to weed emergence after the alfalfa has reached the second trifoliate stage but before it reaches 6 inches in height. Some stunting and yellowing of the alfalfa may occur with postapplications. Do not apply less than 50 days prior to alfalfa harvest for forage or hay. |
| Pursuit 2S | Postemergence | 3–6 fl oz | 0.047–0.094 | Alfalfa and alfalfa-grass mixtures, CREP | Apply to pure stand alfalfa or established alfalfa-grass mixtures in spring or fall when weeds are 1-3 inches in height or rosette width. Include a nonionic surfactant (1 qt/100 gal) or oil concentrate (1 qt/A) plus nitrogen solution (1–2 qt/A) in the spray mixture. Tank-mix with Buctril or Butyrac to broaden control spectrum. Do not apply Pursuit to alfalfa-grass mixtures during the establishment year or to alfalfa during the last year of the stand (crop rotation considerations). Do not feed, graze, or harvest forage for 30 days after application. |
| or | or | ||||
| 70DG (imazethapyr) | 1.08–2.16 oz | ||||
| Raptor 1AS (imazamox) | Postemergence or dormant | 4–6 fl oz | 0.031–0.047 | Alfalfa | Apply to established alfalfa in the fall, winter, or in the spring to dormant or semi-dormant alfalfa or between cuttings. Any application should be made before significant alfalfa growth or regrowth (3 inches). Applications require the addition of an oil concentrate or surfactant plus nitrogen solution. Apply Raptor in 10 or more gallons/A water. A maximum of 6 fl oz/A Raptor per season may be applied to alfalfa. May be tank-mixed with 2,4-DB, Poast, or Select to broaden control spectrum. |
| Roundup / glyphosate | Postemergence | varies | 0.75–1.5 | Roundup Ready alfalfa | In RR alfalfa varieties only, apply 22 to 44 fl oz/A Roundup Weather Max 4.5S or 32 or 64 fl oz/A glyphosate 3S formulations to established stands. Application can be made after the first cutting, and in subsequent years, glyphosate may be applied up to 5 days prior to harvest and when annual weeds are less than 4 inches tall. For perennial weed problems, glyphosate should be applied during early fall. Wait at least 5 days after application before grazing or haying. Sequential applications of glyphosate should be at least 7 days apart. Do not apply more than 4.6 lb ai glyphosate/A/year in crop (132 fl oz/A Roundup Weather Max 4.5S). |
| Roundup 3S² / Roundup WeatherMax 4.5S² / glyphosate² |
Preharvest | 1–2 pt | 0.5–1.0 | Alfalfa or alfalfa-grass mixtures | For use on declining alfalfa stands prior to crop rotation. Apply before last cutting in fall or spring to control certain perennials such as quackgrass. Apply 1 qt at 10 gpa. Harvest 3 to 7 days after application. Deep tillage after harvest improves control. Fall applications are more effective on perennial grasses. Refer to herbicide label for additional application information and use restrictions. |
| Velpar 2L/90DF (hexazinone) | Dormant and between cuttings | 2–6 pt/0.5–1.5 lb | 0.5–1.5/0.41.3 | Alfalfa | Make a single application after alfalfa becomes dormant and before new growth begins in the spring. Where weeds have emerged, include a surfactant. May be applied between cuttings; apply before 2 inches of regrowth is present. Severe injury may result with after cutting applications if significant alfalfa foliage is present at application or air temperature exceeds 90°F. Only corn may be planted 12 months following application. Other crops may be planted 24 months after application. |
| Sinbar 80W (terbacil) | Dormant | 0.5–1.5 lb | 0.4–1.2 | Alfalfa | Apply in fall after plants become dormant or in spring before new growth begins. Apply before weeds germinate or before they exceed 2 inches in height or width. Do not use on grass-alfalfa mixes. Do not replant to any crop within 2 years after last application. |
| Select 2EC (clethodim) | Postemergence | 6–8 fl oz | 0.09–0.125 | Alfalfa, birdsfoot trefoil | Apply to actively growing grasses at the size recommended on herbicide label (generally less than 6 inches tall). Always use a crop oil concentrate (1 gal/100 gal) in the spray solution. May be tank-mixed with 2,4-DB for broadleaf weed control; however, temporary crop injury may occur. For annual bluegrass control, apply 6–16 fl oz before the 4-leaf stage of bluegrass. |
