Herbicides to remove Crabgrass from Bermudagrass hay fields
Although Crabgrass varieties can be an excellent source of forage or hay in a monoculture setting, when it invades Bermudagrass hayfields it presents a major problem to producers. Crabgrass does not dry as readily as Bermudagrass and often does not dry with the ‘quality hay’ look (it’s not a pretty green color that people often misconstrue as an indicator of good hay).
So the problem becomes how to safely remove the Crabgrass without damaging the Bermudagrass in hay fields. There are several options for producers, and each has benefits and drawbacks.
Impose or Panoramic (Imazapic)
Non-Dormant Pasture: Imazapic offers good control of Crabgrass along with other weeds such as sandbur, nutsedges, and vaseygrass, but can cause 30-50% yield loss in the cutting following the application of the herbicide, especially during the summer months when Crabgrass is actively growing. Do not apply imazapic to Bahiagrass or during the spring transition of Bermudagrass. Although severe Bermudagrass stunting should be expected, quick regrowth will occur. An application rate of 4 oz/A will suffice for Crabgrass control. Do not graze or cut for 4 weeks following application.
The following pictures were taken from a Bermudgrass field in O’Brien, FL. The areas within the orange lines are the test trips that were not sprayed with Impose, while the treated areas are devoid of the targeted weeds.
Pastora (Metsulfuron + Nicosulfuron)
Non-Dormant Pasture: Metsulfuron + Nicosulfuron offers good control of seedling Crabgrass in established bermudagrass only, in addition to sandbur, vaseygrass, and established johnsongrass. If the Crabgrass (and sandbur) is taller than 4 inches, the application of this herbicide will only suppress seed seedhead formation. Application rates if 1-1.5 oz/A should be utilized, but not exceeding 2.5 oz/A/yr. If applied to limpograss or bahiagrass, expect severe injury. No grazing or cutting restrictions.
Roundup Weathermax (Glyphosate)
Non-Dormant Pasture: Applications of Roundup Weathermax offer great control of many annual grass in Bermudgrass, including Crabgrass. Application rates as low 6 oz/A have been effective control amounts, and should be applied immediately following a hay cutting. Do not apply more than 2 qt/A/yr, and if applied to a dormant pasture, Roundup Weathermax can not be used again that year.
Dormant Pasture: Apply in mid-late winter before new growth appears. No restriction on grazing or haying, but if used on a dormant pasture, this herbicide cannot be used again during that production year. 11 oz/A of Roundup Weathermax OR 16 fl.oz/A of Roundup Ulta (or other 4 lb formulation) is the recommended application rate.
Prowl H2O (Pendimethalin)
Dormant Pasture: Prowl H2O provides preemergence control of Crabgrass and some other weedy grasses, but escaped weeds should be expected. Rainfall or irrigation is required to activate the herbicide within 2 weeks of application, and offers no control over plants that have already emerged. Use 1.1 – 4.2 qt/A.
Read the Label, Read the Label, Read the Label
Always be sure to read the label and follow the guidelines set forth for any herbicide used.