Guidelines to Follow For Applying Herbicides To Dormant, Warm-Season Turf

It’s that time of year again. Golf course superintendents with warm-season turf are currently loading their sprayers for broadleaf and annual weed control with a non-selective herbicide, like Roundup or glufosinate, or planning to do so. Ensure the applications go smoothly with these guidelines.

Assess Your Warm-Season Turf’s Dormancy

What is your turfgrass’s current level of dormancy? Is it just going into dormancy? Is it in full of dormancy, or is it coming out? You don’t want to spray herbicides on warm-season turf that is going into dormancy or coming out. Warm-season turf is sensitive to herbicides, especially during those transition periods. If the turfgrass plant is not in full dormancy during the application, delayed green-up, injury, and even death could be witnessed during the spring transition.

Physical Examination for Dormancy

Assess your turf’s dormancy by getting dirty. Dig down into the turf canopy and examine the crown, stolons, and leaf tissue for green. Please keep in mind that non-selective herbicides are going to kill any and all green and actively growing plants. If you discover any sign of green tissue on bermudagrass or zoysiagrass, a nonselective herbicide application is not recommended. It is also a good idea to avoid spraying when the turf is over-saturated from heavy rain, frozen or rain is forecasted within 24 hours of the application.

Use Tracker Dye or Foam Marking System

Use a tracker dye or foam marking system to ensure that you’re applying the chemical accurately and evenly. Tracker dyes, like Super Signal Blue from Precision Laboratories, will ensure no areas are missed or double sprayed. The tracker dye also alerts your crew and others to where the non-selective herbicide was sprayed, so they won’t walk or drive across these areas and track the herbicide. Tracker dyes typically dissipate within a week or so.

Utilize Adjuvants in Your Tank

Put an adjuvant in your tank. Adjuvants, like Border 2.0 and Chem-Stik LpH from Precision Laboratories, will help control the droplet size and manage drift. This allows your non-selective herbicide to attach more uniformly to your target species and improves the overall performance of the herbicide.

Add Pre-Emergent Herbicide in Your Tank

Add pre-emergent herbicide, like oxadiazon or prodiamine, to your tank, especially if your planning on doing spilt apps. You can think of this as “killing two birds with one stone.” You’ll save labor, your equipment, and fuel usage. The pre-emergent will not break down until microbial activity increases. So, make use of your tank mix options. One great option is ArmorTech Kade.

Wait and Watch Traffic

Ensure the non-selective herbicide has an appropriate time to dry on the plants before you allow any usage following the application: no motorized vehicles, no foot traffic. Non-selective herbicides will track, and they can track onto non-targeted turf areas and cause damage.

Allow time for the herbicide to do its job. If you put down a moderate or medium rate of Roundup, you’re probably looking at 10-21 days before you’re going to see the herbicide take your targeted plants. Just be patient and give the herbicide time to work.

Calibrate

Don’t forget to ensure your sprayer is calibrated before you go out. Also, remember to follow the pesticide label guidelines when considering rates and consider using the lowest rate possible to achieve your desired result.

Be cautious and patient during these applications! The cold temps can increase the time for the herbicide to take effect. For more information on product selection for your dormant, warm-season turf, talk with your Advanced Turf sales rep.

*Special thanks to Advanced Turf Sales Rep Jason Renfrow for contributing to this blog.