April 28, 2007 Article
by David Rodriguez
People who love their lawns in this area are REALLY upset about Brown patch fungus damage to the appearance of lawns. Most of the grief is about the damage that occurred last fall. As the old saying goes, “It doesn’t do any good to cry about spilled milk!” or, as tough Texans like to say, “It doesn’t do any good to shut the corral gate after the livestock are running loose!” The damage done by Brown patch was done last fall AND TREATING THE DAMAGED AREA NOW WILL NOT HELP! The areas affected by Brown patch last fall will be slower to green up this spring but THEY WILL GREEN UP because BROWN PATCH FUNGUS DOES NOT KILL! Just apply your spring application of fertilizer AFTER you have mowed the lawn twice and ignore the weakened Brown patch affected area. In several weeks you will not be able to find it. If you want to insure a faster and complete coverage of the damaged area, you can plant some plugs of grass in the most barren areas.
I AM NOT saying that your troubles with Brown patch are over. Given adequate moisture and high humidity, plus temperatures in the 70’s and 80’s, means more plant disease-especially Brown patch. But you DO NOT need to treat until you see the first signs of Brown patch reappearing in exactly the same areas that were affected last fall and that were so slow to green up this spring. Once the damage begins to appear, you MUST treat immediately with the best fungicide in the proper manner to avoid severe damage to the lawn this spring and subsequent ugliness all summer long.
Fungicides cannot repair the damage done by fungus; they can only prevent the occurrence or spread of it. The most important concept to remember in disease control is “an ounce of prevention is worth a pound of cure.” This is the opposite of insecticides, most of which kill insects on contact or when the insect eats the pest-control material covering the plant. Therefore, fungicides should be applied when the opportunity for disease raises its ugly head. Cool temperatures, high humidity and available water are the perfect conditions for most fungal diseases to attack. Increased growth of the grass makes it more susceptible to Brown patch. This means that all of those folks who “love” their grass so much that they fertilize it twice a month and water it every three days actually STIMULATE Brown patch proliferation. All of that fertilizer may make the lawn nice and green for a while but just wait until those cute brown spots begin to grow aggravated by watering too much!
Brown patch is identified as a circular area in the lawn, usually 3 to 10 feet in diameter. In the edge of the area you will see browning or yellowing grass, yet the interior of the circle may be a more healthy green. Pull blades of grass at the edge of the circle. If the blades pull easily away from the stems and look brown and rotted at the base of the blades, then your lawn does have Brown patch and should be treated quickly. Bermuda grass lawns have much less problems with Brown patch but can still contract the disease.
Chemical controls recommended for Brown patch are l) terrachlor – PCNB (ex. Turfcide, Fertilome – Lawn Disease Control) and 2) bayleton (ex. Greenlight Fung-Away). The best product seems to be the granular form of terrachlor but, because it is so expensive, you must use it judiciously and precisely. Watch for the small yellow patches (NO! It’s not the neighbor’s dog violating your lawn space and depositing liquid waste!). Treat the spot IMMEDIATELY with terrachlor granules and then treat a 3-foot area around the spot. To avoid spreading the fungus DO NOT WALK THROUGH infected areas when they are wet or let pets run through the wet grass-a pet’s feet are smaller but they have more of them. DO NOT, hear me, DO NOT MOW GRASS WHEN IT IS WET! Not only will it stain your clothing and clog the mower but, as you trot merrily around the damp or wet lawn, you become a disease spreader. Worse than Typhoid Mary, your wet body parts and the lawnmower act as a vehicle of transport for one of the worse fungus diseases of turf grass in Texas-Brown patch.
Another way to discourage Brown patch after the rains of spring is to eliminate watering in the evening. Water droplets that stay on the grass all night will spread the Brown patch spores. Therefore, water in the early morning hours so that the grass will dry out during the day and before nightfall. Thorough watering of lawns once a week is normally sufficient. The people who love their lawns so much that they give grass a “cool drink” every couple of days during the summer can actually stimulate Brown patch disease in the middle of the summer.
Now you know the “game plan” to protect your precious lawn from one of this area’s most serious lawn problems in the fall and spring Brown patch.
But, what if you have Brown patch-like symptoms in the heat of the summer? Unlike Brown patch that is normally a circular area with the edge of the circle having browning or yellowing grass and the interior of the circle having a more healthy green appearance, this patch disease symptom has brown, dead grass throughout the circle. This summer-patch disease is referred to as Take-All Patch. The products used to control Brown patch DO NOT control Take-All Patch. For complete information about control of Take-All Patch, see: http://www.plantanswers.com/root_rot_fungus.htm and the bottom section of
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David Rodriguez is the County Extension Agent-Horticulture for Bexar County. He represents Texas Cooperative Extension with the Texas A&M University System. To get questions like these answered, call the Bexar County Master Gardeners Hotline at (210) 467-6575, e-mail questions to firstname.lastname@example.org, or visit our County Extension website at: https://bexar-tx.tamu.edu, click under Horticulture and Gardening.
Special Note: Listen to a live broadcast of the Garden Show with David Rodriguez and Bill Rohde on WOAI 1200 AM every Saturday morning, between 8:00 and 11:00 a.m., call in your gardening questions at (210-737-1200 or 1-800-383-9624). Check it out!