Summer Weed Control In Bermudagrass

Daniel Gill, Koske, Thomas J.  |  10/4/2004 4:25:27 AM

Maintaining good Bermudagrass turf primarily includes adequate fertility, mowing and weed control, says LSU AgCenter horticulturist Dr. Tom Koske.

"In fact, part of the weed control effort is to provide adequate fertility and proper mowing."

Some Louisiana lawns and most, if not all, of our athletic, playground and golf turfs are Bermudagrass.

The LSU AgCenter horticulturist says proper Bermudagrass mowing follows the one-third rule. Never cut off more than the top one-third of the grass shoots. In other words, if you mow Bermuda at 1 inch, it's time to mow whenever it reaches 1.5 inches high. He notes that common Bermudagrass is mowed at 1.25 inch to 1.5 inch. Hybrid Bermudas are clipped to 1 inch or less.

"Regular mowing foils many weeds and allows the Bermudagrass to be thick and smothering," Koske says, adding, "Adequate fertility also allows it to be competitive with weeds."

He points out that a soil test will give the best recommendations on fertilization, but he offers several general suggestions on fertilization and weed control.

• Keep the soil pH to at least 5.8 or higher. You need about 150-50-100 in fertilizer per acre to be applied in four or five split applications from April through August. A fertilizer application is best scheduled following a herbicide application, if the schedule permits.

• General broadleaf control is often done using 2, 4-D in three-way or two-way blends with dicamba and others. The main selective weed killer for Bermuda is MSMA or DSMA. These arsenicals are good on grassy weeds and smutgrass. They can be tank- mixed with metribuzin or 2,4-D if broader control is necessary.

• To improve control and minimize Bermuda discoloration, repeat applications at the lowest recommended rate are necessary. Repeat the arsenical application using the 2 pounds per active ingredient rate after seven to 10 days on tougher weeds. Repeat phenoxys in two weeks if needed. Fertilize after final herbicide application to reduce off-color time.

• Take out bahiagrass with treatments of the new Manor herbicide or arsenicals. Control sedges with Basagran, Image, Manage or repeat applications of arsenicals.

• Your control often is no better than your application, so set up your equipment right and calibrate it to within 10 percent error. Set spray output between 18 and 30 gallons per acre.

• Don’t overlook the edge of your field. That’s where weed control begins. Sideline weeds left untreated will produce seeds that will wash or be tracked onto the field.

"Good athletic turf is important for the player's safety and/or the quality of the game," Koske says, adding, however, "Good turf doesn't just happen. It requires a plan, effort and some properly spent dollars."

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