Brown patch

Brown patch

Brown patch can spread fast and wide, so be on your guard. It may be caused by various diseases or pests. Two of the most prevalent invaders are the rhyzoctonia fungus and the chinch bug. The fungus is most likely to appear when the weather is humid, while the bug thrives in dry periods.

Brown patch and chinch bugs

Chinch bugs usually start being active in the first weeks of summer, although this can change form year to year as well as vary from one location to another. These pesky little insects can suck the sap out of your turf grass, leaving brown, sunken patches that tend to get larger and eventually join together, leaving large portions of dead turf on your lawn. During longer periods of hot, dry weather, they tend to be very active and can virtually destroy your lawn.

Knowing if you have the bug

Perform this little test to see whether or not you have chinch bugs. Take a large used can and remove the bottom part, thus turning it into a cylinder. Place this cylinder on a section of your lawn where you think bugs may be active (don’t do it in a dead section – the bugs aren’t interested in that section anymore) and thrust it at least one inch into the ground. Then fill the cylinder with water. Wait a few minutes. Any bugs present in that small section of turf grass will float to the top.

Fighting the bug

If your lawn is under a mild attack, consider using a soft approach. Watering your lawn regularly will tone down the problem. Over-seeding with turf seeds that contain endophytes, such as Fescue and Ryegrass, may also help in the long run.

In those cases where powerful, immediate action is called for, the use of pesticides is recommended. You should choose the right product and make sure that you follow the directions carefully, as pesticides may cause more damage than good. Remember that your lawn is a living environment. Killing everything in sight won’t make things better.

Solutions containing clothianidin are your best choice against chinch bugs. When applying such pesticides, you should wear protective clothing and gloves.

Lawn fungus

When the weather gets hot and humid, lawn fungus can spread in a matter of hours, leaving brown patches on your lawn. If the weather changes and gets cooler and less humid fast enough, the rate at which the disease progresses can slow down and the grass may recover by itself in a few weeks time. But if it stays hot and humid for a while, consider taking action.

This lawn disease can be identified by the brown, round patches it leaves on your lawn. It can come out as small patches that multiply or as a single patch that gets larger and larger. There is in some cases a thin, dark ring around the patches. Note that since this is a warm weather disease, warm weather turf grasses have better natural protection, as opposed to cool weather grasses. Kentucky bluegrass, for instance, is more resistant than Ryegrass.

The root of the problem is a fungus named rhizoctonia solani. This plant thrives in warm, humid conditions. It especially likes young grass and seedlings and its growth can be fueled by nitrogen rich fertilizers.

Fighting the fungus

The first thing to do to deal with fungus caused brown patch is to control watering and fertilization. Consider using green fertilizers which are known to be effective against moss.

If possible, give your lawn more sunlight and air. Try not to feed the fungus by seeding your lawn when the weather is warm and humid. And especially don’t try to fight this by over-seeding the brown patches, as you would only fuel the growth of the fungus.

There are some pesticides that are known to be good against this disease. The fungicide azoxystrobin, for example, is a good example. It will not kill it, but it will impede its proliferation while the muggy weather lasts. This product has low toxicity in most environments, but may not be an environmentally optimal choice near lakes and streams, as it is known to have negative effects on some fish species. For more information, visit your local nursery and ask for a pesticide that can effectively and safely deal with the fungus rhizoctonia solani. When you apply the product, make sure that you follow the directions.

If you’ve been having this problem before and know that you are likely to get it again, it may be a good idea to use the pesticide before the patches actually appear.


By the way, some people seem to confuse brown patch and thatch, but the latter is a completely different problem.

Lawns are not always easy to keep top shape. To maximize your chances, you must have a comprehensive lawn care program.