View Mobile Site

Dollar spot, brown patch prove problematic diseases

POSTED: May 24, 2013 1:00 a.m.

This spring has been wet and cool. It always amazes me how different one spring from the next can vary so much.

Everyone seems to be in the starting blocks, eager to get out there and plant their summer veggies or improve the flower bed. Once the soil can be worked, a fury of activity will happen across the county.

In the meantime, gardeners should look at their lawns for problems. A couple of diseases I want to discuss may show up if all conditions are right.

The first one is dollar spot. This disease can be a problem in tall fescue and Bermuda. When temperatures are between 60 and 85 degrees and the humidity is high, you generally see a lot of dollar spot. Symptoms are sunken, circular patches measuring up to several inches. The patches turn from brown to a straw color and merge if they become large enough.

You can do a lot of things to manage this disease. One is to use an adequate level of nitrogen fertilizer, but don’t overfertilize. It will just end up in the lake and burn your grass.

Mow regularly to reduce the thatch.

Watering is not an issue now — thank goodness — but if you do water, make sure it’s deeply and infrequently. This will help the plant develop a strong and deep root system. If possible, remove the dew early in the day.

Brown patch is the second problematic disease. All types of grass are susceptible to it and it favors high humidity and temperatures higher than 80 degrees in the day and 60 degrees at night. Symptoms of brown patch can vary, but it typically causes rings or patches of affected turf 5 inches to more than 10 feet in diameter. After the grass dies in the middle of the patch, new leaves of grass can emerge, making it have a ringed effect.

Managing for brown patch is a little different than with dollar spot in that you do not want to use adequate amounts of nitrogen. Instead, provide a moderate amount of phosphorus and somewhat high amounts of potash or potassium.

Other things to do are increase your mowing height, improve air circulation, irrigate early in the day (after dew fall but before it dries), reduce thatch and add lime to the lawn if the pH is less than 6.5.

For both diseases, fungicides are available to use to help fight them. Think of a fungicide as just another tool to use in addition to all of the management techniques already discussed. Some products that work well for both diseases are captan, maneb, myclobutanil and thiophanate methyl. Only one of these products should do the trick, so don’t worry about having to buy half the store’s inventory. If you have trouble deciding which one to use based on its brand name, use these common names, like I listed here, that are on the ingredients list to decide.

Disease management in a lawn is not so much different than what we have to do to stay healthy. Provide your lawn with the right amount of fertilizer, reduce as many elements stressing it and maintain and cut the lawn to get the best growth results.

Michael Wheeler is county extension coordinator for the UGA Cooperative Extension office in Hall County. You can contact him at 770-535-8293, www.hallcounty.org/extension. His column appears weekly and on gainesvilletimes.com/life.


Contents of this site are © Copyright 2010 The Times, Gainesville, GA. All rights reserved. Privacy policy and Terms of service

Powered by
Morris Technology
Please wait ...