Bermuda grass with a large disease patch
Even in the cooler months, it's important to understand the care your lawn needs. The two main problems of turfing during the winter months are mushrooms with brown spots and weeds in winter. Both problems can be severely affected by excessive soil moisture. Here are some other common fungi and diseases to keep in mind during the winter months.
DISEASE: Large patch and brown patch diseases of lawn grass
PATHOGEN: Rhizoctonia solani
HOST: Lawn grasses in the warm and cool season
Rhizoctonia solani is a pathogen that causes disease with large spots in lawn grass in the warm season and disease with brown spots in lawn grass in the cool season.
Large patch and brown patch are the same disease caused by the same fungus, but have different names depending on the type of grass.
Large patch mushroom is very common in warm seasons such as St. Augustine, Centipede, Bermuda and Zoysiagrass. Shade tolerant varieties from St. Augustine such as Seville are often the hardest hit.
Brown patch mushroom is commonly found in cool season lawns such as bentgrasses, bluegrasses, fescue and ryegrass.
Large patch on StAugustine Grass
The fungus attacks the base of the leaf sheath, on which the blade is attached to a plant stem.
The easiest way to distinguish Large and Brown Patch from other causes of lawn decay is to pull the blade. Affected leaf blades easily detach from the Stolon and slide out of the casing. Another examination of the base of the blade shows tissue soaked in dark water.
The pathogen causes symptoms that start as spots and get bigger with the spread of the disease. It will damage the leaves, but will not damage the stems or roots, so the turf grass will start to repair in the middle, sometimes giving it a donut-like look.
This fungus develops fastest when the air temperature is below 80 ° and there is free moisture on the leaf. The infection is triggered by rainfall, excessive watering, or prolonged periods of high humidity, which causes the leaf canopy to be wet continuously for 48 hours or more.
These conditions occur most frequently and over a longer period in autumn and late winter / early spring. High levels of readily available nitrogen also increase the severity of the disease. Fungal activity generally stops when the air temperature reaches 90 °. Therefore, it is usually not active in summer.
The disease triangle is a concept that helps us understand what is required for an active disease. The disease triangle includes the following:
1. Host: The host is the lawn grass.
2. Pathogen: Rhizoctonia solani.
3. Favorable conditions: Excessive moisture and plant stress are examples of favorable conditions.
Rhizoctonia solani is a soil-borne pathogen and can cause disease if conditions are favorable. By reducing favorable conditions such as prolonged leaf moisture and using a fungicide, the fungal activity is suspended and the grass can recover. When the seasonal conditions change, the mushroom activity stops due to the lack of favorable conditions. Our team members apply fungicides accordingly and gently rinse the soil so that the material reaches the plant through the roots and reaches the place of attack. A follow-up visit in 21 to 28 days is required to ensure recovery.
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