South Africa Turf Disease Guide - Pythium Blight

Disease and Insect Control

17.11.2021

South Africa Turf Disease Guide - Pythium Blight

Causal Agent:

Pythium aphanidermatum, other Pythium species

Susceptible Turfgrass:

Most species of warm and cool season turfgrass

Symptoms:

Pythium Blight appears suddenly during hot, humid weather. This disease causes greasy, brown circular spots that are initially about 2 cm to 5 cm in diameter and then rapidly enlarge in size. The spots are water-soaked and dark-coloured early in the morning. They also form fluffy white masses of fungal mycelium (cottony blight) and can coalesce to form large, irregular areas of dead turf. Infected patches may appear brownish-orange in colour.

Conditions Favouring Disease:

Pythium Blight favours night temperatures of over 20°C. It occurs in areas that experience more than 10 hours a day of foliar wetness for several consecutive days. It is found in the wettest areas of turf and in areas with poor drainage and air circulation. Lush-growing turf growing under nitrogen fertilization is particularly susceptible to the disease.

Integrated Turf Management Tips:
Avoid mowing wet turf when the foliar mycelium is evident to minimise spreading the disease • Reduce thatch
Avoid excessive nitrogen application during hot weather
Increase air circulation to speed the drying process of the turf
Minimise the amount of shade
Irrigate turf early in the day. Avoid late-day watering
Improve soil drainage
Irrigate turf deeply and as infrequently as possible and Bermudagrass

Find out more about Pythium Blight by visiting our specialist horticulture website here.

Just tap the links below to read about other turf diseases. Or download the full free guide at the bottom.