No matter where you live in the continental U.S., your sunny lawn is likely to be attacked by brown patch disease in late spring and summer. All cool and warm season grasses fall victim to the disease. Cool-season grasses like Kentucky bluegrass, perennial rye, fine and tall fescue first experience brown patch in mid-June. Warm-season grasses like bahia grass, bermudagrass, St. Augustine grass and zoysia witness the first disease attacks in May.

How can you tell your lawn is under attack by the disease?

Brown patch, also known as rhizoctonia, traditionally begins when environmental conditions are in place: daytime temperatures above 65 degrees (18C), and nighttime temperatures remain above 60. Humid, rainy weather and wet lawns overnight spread the disease quickly as does an application of quick-release nitrogen.

Disease symptoms appear as circles or irregular patches of discolored grass, perhaps only a few inches wide, but later increasing to several feet in diameter. Grass blades usually show lesions with a dark brown border. Lawns that are cut high seldom show lesions on leaf blades, yet the blighted grass is easily identified.

The way you care for the lawn can minimize the effects of the disease. Avoid applying nitrogen toward late spring when brown patch is likely to erupt . . . cut the grass on the tall side, usually 3 inches for cool-season grasses, just below 2 inches for warm-season grasses . . . if you water, irrigate early in the day, generally before 10 . . . collect grass clippings while the disease persists on the lawn . . . cut healthy grass first, diseased grass last.

If you inspect your lawn in the early morning hours (between 6 and 7), you will quickly see the disease infecting healthy grass. Look beyond the center area of infection, toward the border. There, you will find white cotton-like filaments attached to the lower parts of the grass. This is where the disease is multiplying to infect healthy grass plants. If you stand directly above the infected grass, you may see a bluish-purple “smoke ring” encircling the diseased grass. As moisture disappears later in the morning, both the smoke ring and white filaments disappear.

Because brown patch is such a volatile disease, homeowners have long since relied on fungicides to control the disease. Over the past generation, a host of products which were labeled for brown patch control have been withdrawn from the market; only a few are available today. Granular Daconil, once a standard for disease control on home lawns, was de-listed by EPA in 1999 for consumer use. In recent years, only granular Bayleton continues to be available for brown patch control on residential lawns. Through 2002, we strongly recommended Bayleton for disease control, but probably not for the future. Why?

When we received a technical on turfgrass research projects conducted in 2001, we weren’t happy with some of the results. In the matter of brown patch control, Bayleton was deemed the worst of 18 products tested. With four applications of Bayleton from July 2 to August 8, Bayleton recorded only five percent disease control. In one test where nothing was applied to the turfgrass (check plot), only 80 percent of the plot fell victim to brown patch disease. The study was conducted to evaluate various fungicides, rates of application, and tank mixtures for controlling brown patch.

Imagine, Bayleton had the poorest track record for disease control. It raised serious questions. Had we known the facts, we never would have recommended Bayleton to consumers for brown patch control.

With such high stakes, we had to find out what went wrong with Bayleton in the 2001 turf trials. We were on the phone with chemical experts at Bayer (now Bayer Environmental Sciences) why their fungicide didn’t work. Bayer chemists told us there are several strains of disease spores responsible for brown patch, but, unfortunately, Bayleton only controls one of them. In the 2001 test, it’s obvious that multiple strains of disease spores caused brown patch, but Bayleton wasn’t able to deal with all the strains. In the plot treated with Bayleton, 95 percent of the grass died. It was the worst performance of all fungicides in the university test.

Other points of interest:

* 32 plots in all, each 3 by 6 feet;

* plots were fertilized in mid-May with 0.8 lbs. of nitrogen, early June with 1 lb. of nitrogen, and one lb. of nitrogen in mid-June to fuel the disease;

* from mid-July to early August, plots were lightly irrigated and covered at night with thin black plastic to reduce radiational cooling;

* 18 fungicides at varying application rates were tested for performance.

With the exception of Bayleton, all fungicides tested were “restricted use pesticides” not available to homeowners. Restricted products can only be applied by certified applicators licensed by state governments and municipalities. The fungicides are unknown to consumers, but it’s good to know what they are and how much they cost. Some examples:

* Chipco, gallon, $107.50

* Chipco 26019 WP, 16 ounces, $27.60

* Compass 50WG, 8 ounce package, $137

* Heritage 50WG, 16 ounces, $355

* ProStar 70WP, 16 ounces, $38.50

Now, everything boils down to the options available to homeowners to get out from under brown patch disease every summer. What can we do? The more you think about it, you realize our hands aren’t exactly tied and, as consumers, we have a lot more clout than meets the eye. Then what?

Let’s go back to the university tests and look at the possibilities, such as “Compass.” Certainly, Compass is downright expensive, but in the university tests they applied only 0.15 ounces at the rate for 1,000 square feet and achieved 99.5 percent control of brown patch. To put it better perspective, less than 4 grams of Compass over a thousand square feet practically eliminated all brown patch in the university trials. Only one product matched the disease control of Compass, and this was from a product still in the experimental stage.
The university used this latter product under an Experimental Use Permit (EUP).

True, Compass remains a “restricted use product,” but if it were available in lower concentration in granular form for homeowner use (an L&G label), what would be its effect on homeowner lawn maintenance across the nation? Gangbusters!

Look at it another way: Bayer Environmental Science owns patent rights to both Bayleton and Compass! If homeowners had access to granular Compass at lower concentrations than the professional product, imagine what it would do for your lawn! It’s very possible you would never see brown patch on your lawn again!

If you would like to see Compass made available to home gardeners, you can help send a message to Bayer of how critical it is for Compass to be made available to you for brown patch control. A letter to the chief executive officer of Bayer would be a major step in that direction.

Send your note or request to Daniel H. Carrothers, CEO, U.S. Green Industry Business, Bayer Environmental Science, 95 Chestnut Ridge Road, Montvale, NJ 07645. He is the executive in charge of Bayer’s line of fungicides, herbicides, insecticides, turf/nursery/ornamental products.

We have drafted a brief letter to Mr. Carrothers that you may send or adapt on your own:

Dear Mr. Carrothers:

Please help us save our lawns! We know that granular Bayleton won’t control brown patch as we would like, but you have a miracle-performing product that does: Compass. While Compass is a professional, restricted product, home gardeners need such a product if we are to grow healthy grass every year and not be tempted to pour concrete.

Please exercise your authority and start the process of registering “granular Compass” for homeowner use to control brown patch. In one university test of 2001, Compass controlled the disease 99 percent. Without Compass, we may have no choice but to pour concrete.