Take-all Patch:
Take-all patch is the bane of lush lawns across Texas. This fungal pathogen primarly attacks St. Auguastinegrass, especially in stressed or weakened conditions. However, on occasion, take-all patch has been identified in bermudagrass and zoysiagrass, as well.
The fungi target the grass and cause decay in the root system. This, in turn, stops the grass plant’s development, resulting in yellow stolons (runners). Look for the telltale irregular patches of dead grass. Disease activity may show up any time during the growing season, but is most prevalent in late spring and fall when soil temperatures are in the 60-to-65-degree range.
In an effort to maintain turf vigor it is tempting to apply fertilizer and/or water when the lawn isn’t as green as it should be. Take some extra time to investigate the situation more closely. Localized patches of discoloration are likely areas of disease or insect activity. An overall pale appearance, however, may be a fertility or water issue.
Avoid creating conditions that invite disease invasion and apply water and fertizlier at times less conducive to fungal growth. Make fertilizer treatments between April 15 and October 1, and always irrigate St. Augustinegrass in early morning hours to minimize prolonged moisture on its leaf surface.
Alkaline soils are another culprit that encourage the development of take-all patch. Studies show topdressing the lawn with a half-inch layer of Canadian peat moss alleviates the symptoms of take-all patch. The peat moss layer creates an acidic environment at the soil surface that is unfavorable for the take-all patch fungus to grow.
Fungicides can be used once the pathogen has attacked the host plant. Labeled chemical controls for take-all patch include F-Stop (myclobutanil), Bayleton (triadmefon) and Banner (propiconazole). Read and follow all label directions. Examine the label closely to make sure the disease is still covered on that particular product, as labels are frequently amended for specific plants and diseases.
Each lawn has its own unique challenges. Experiment with the different methods and information to reduce the likelihood of a take-all patch invasion.
About the author: Mike Sutton is a horticulture graduate of Purdue University with more than 20 years’ experience with turfgrasses in Texas.
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