Brown Patch / Yellow Patch

The brown patch has two pathogen types with different temperature requirements. The optimum temperature for Rhizoctonia solani is 25 - 30 °C, with warm nights at the same time. Rhizoctonia cerealis, on the other hand, requires a cooler temperature of 10 - 20 °C.

The damage appears as light brown-reddish, 5 to max. 100 cm large, irregular spots, sometimes with a gray-blue ring at the edge of the infested areas. Rhizoctonia cerealis tends to show yellowish, ribbon-like spots. The roots and stems can be infested. The root collar and vegetation point usually remain intact. For this reason, any damage caused grows back relatively quickly. Only rarely does the lawn die completely. However, mixed or secondary infections are common.

Infestation-promoting factors:

• High humidity, calm and dew

• Cut too deep

• Excess nitrogen and shock growth

• Nutrient deficiency

• All types of grasses can be infested

Preventive measures:

• Balanced and even nutrient supply

• Avoidance of rapidly soluble forms of nitrogen

• Fertilization with long-term nitrogen

• Targeted potassium applications during the summer months

• Optimize the irrigation technique, irrigate in the early morning hours to allow the crop to dry quickly

• Remove dew (e.g. by using anti-dew agents and penetrating wetting agents)

• Raise cutting height

• Reduction of lawn thatch

• Optimize air supply