Pythium Blight

Susceptible turfgrass: All turfgrass species, especially annual bluegrass, perennial ryegrass, bentgrasses, and tall fescue and Bermuda grass.

um spp.

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 fertilisation is particularly susceptible to the disease.

Integrated turf management

• 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.

​Use Subdue Maxx or Heritage for fungicidal control

Heritage has label recommendation for Pythium blight control in South Africa.