Root Rot (Pythium Rot)

Root rot, also known as Pythium, is often mistaken for drought damage at first. The lawn appears slightly bluish-gray and limp. One thing is certain, however:
Pythium is a typical stress-related disease that affects only weakened turfgrasses.

If weakened plants are exposed to unfavorable weather and soil conditions, the disease can spread very quickly across large areas of the lawn.

Factors That Promote Infestation

The following conditions are particularly conducive to the development of root rot:

– high daytime temperatures above 30 °C combined with high humidity
– Nighttime temperatures above 20 °C
– high soil temperatures
– Soil compaction
– excessive nitrogen application
– pH level too high
– water-saturated soils (waterlogging)
– Dew, shaded areas, lack of air circulation, and calm conditions

How to Effectively Prevent Root Rot

It is difficult to combat this problem directly—which is why prevention is the priority:

– Optimize watering: it's better to water in the morning than in the evening
– Avoid waterlogging and ensure good drainage
– Eliminate soil compaction through deep loosening or aeration
– Ensure a consistent and balanced supply of nutrients
– Do not use too much nitrogen
– Remove thatch from the lawn regularly (scarifying, aerating, or using a lawn aerator)
– Check the pH level regularly and adjust it as needed
– Determine the actual nutrient requirements, ideally through a soil analysis