June Turf Tips - Commercial

Jeffrey Derr and Adam Nichols

Here are some things to think about turf wise over the next 3 months. To assist those that read our newsletter, we have decided to prepare separate sections of our turf tips for homeowners and commercial applicators.  Specific products mentioned are for illustrative purposes, with no discrimination intended for products not mentioned.

Turf Management Commercial Lawn Care Operators

Tall fescue:

For those maintaining tall fescue, keep an eye out for brown patch disease. This fungus infects tall fescue especially under warm, humid conditions we see during the summer.  Preventative applications of a fungicide containing azoxystrobin, which is available in granular and sprayable form under the Heritage name or in combination with propiconazole under the Headway name. Avoid frequent irrigation as this can create conditions for the disease to build up. If desired, only apply low rates of nitrogen (< 0.5 pounds per 1000 square feet per month). 

If you have not done so, apply the second application of your crabgrass preventer if using a split program.  With all of the recent rain, much of the March treatment has broken down, which can result in new germination of crabgrass. Apply appropriate treatments for emerged crabgrass, broadleaf weeds, and yellow nutsedge as needed. Halosulfuron, sulfentrazone, bentazon, mesotrione and imazosulfuron are options for yellow nutsedge control.  Hard to beat a triclopyr product for control of wild violets and ground ivy.  Otherwise, utilize a 3-way or 4-way product for control of emerged broadleaf weeds, ideally using an amine formulation.

If bermudagrass (often called wiregrass) is a problem, one could apply  Acclaim Extra, alone or in combination with Turflon Ester, or use a Pylex plus Turflon Ester application. Space repeat applications of Pylex plus Turflon Ester at least 3 weeks apart and avoid applications during hot humid weather. Options for crabgrass control include Acclaim Extra, quinclorac -containing formulations, Tenacity, and Pylex.

If annual bluegrass (commonly called Poa) is a concern, one control option is to apply a crabgrass preventer, such as pendimethalin, dithiopyr, or prodiamine, in mid- to late-August as annual bluegrass usually starts germinating in early September.  The crabgrass preventers are often sold on a fertilizer granule. The problem with these combination products is in providing the desired herbicide rate, you may not be applying the appropriate fertilizer rate for that time of year, or conversely, applying the desired fertilizer rate may not provide the preferred herbicide rate.  Applying a herbicide product separate from a fertilizer product solves this problem. The downside of applying a crabgrass preventer in August is that in most cases you will not be able to overseed as these chemicals not only prevent successful germination of annual bluegrass, they also  prevent establishment of tall fescue from seed. One may be able to make an early application of a product such as Balan, and then delaying overseeding until 8 or more weeks later. Overseeding by itself reduces annual bluegrass populations through competition.

Warm-season grasses (bermudagrass, Zoysia, St. Augustine, Centipede):

Now is the time to fertilize since these grasses are actively growing during the summer months and it also is the time to do cultural practices like dethatching or aeration.  Move plugs to fill in bare spots of St. Augustine and other warm-season grasses. Bermudagrass, zoysia , and centipede can also be seeded in June or July.  

Options for control of emerged crabgrass in bermuda and zoysia include Drive or combination products that also contain quinclorac, or Manuscript. A crabgrass preventer can be applied in August for annual bluegrass control in established warm-season grasses, but there are additional options later in the year. Do not apply a crabgrass preventer to newly-seeded turfgrasses. Recognition plus Fusilade provides an option for crabgrass control and bermudagrass suppression in St. Augustine and zoysia.  Recognition alone provides sedge and cool-season grass control. A number of options are available for sedge control in bermudagrass and zoysia through use of Monument, Katana, or Certainty, along with products containing halosulfuron, sulfentrazone, or bentazon.

For broadleaf weeds, apply a three-way or 4-way broadleaf herbicide, ideally an amine formulation.  Do not apply a triclopyr-containing product to bermudagrass.  For St. Augustine, use a broadleaf herbicide for sensitive southern grasses or test a combination of Recognition with a triclopyr product. Metsulfuron  is another option for broadleaf weed control in bermudagrass and zoysia.