All you need to know about Pythium spp.

What is pythium root dysfunction and what causes pythium fungus?

Pythium root dysfunction is a turfgrass disease triggered by pythium fungi. These fungi invade the roots of grass, impeding their capacity to draw in water and nutrients from the soil. When pythium infects turf, it can lead to oddly shaped brown spots and the turf grows at a sluggish pace. This disease is particularly troublesome on golf course greens, particularly creeping bentgrass.

Pythium root dysfunction often starts as small, scattered, yellow patches of turf, typically measuring between 4 to 7 centimetres in diameter. These patches can rapidly expand and merge, causing further damage to the turf.

What are the common symptoms of pythium?

Pythium root dysfunction is a disease of young stands (< 8 years old) of creeping bentgrass turf.

Symptoms are most severe in high sand-content root zones. Symptoms of pythium root dysfunction typically appear during the summer months during periods of heat and drought stress, however, patches may develop at any time during periods of warm and dry weather.

Initially, symptoms appear as circular areas of wilt, chlorosis, or drought stress that range in size from 4 to 16 cm in diameter. These areas progress to larger, irregular patches of yellow, and orange foliar decline ranging in size from 16 to 50 cm. Eventually, if the affected areas are untreated, large turf areas can die.

Root depth within affected areas may be significantly reduced compared to unaffected turf areas. Affected roots have bulbous root tips, lack root hairs, and have a light tan colour.

Image 1. Progression of pythium root dysfunction symptoms to larger, more irregular patches on creeping bentgrass putting green. Note how the stand symptoms have a more yellow-orange appearance when compared to the initial symptoms.

How is pythium root dysfunction diagnosed?

Diagnosis typically involves visual inspection of the affected plants and their roots. Conducting laboratory analysis is a reliable method to confirm the presence of pythium species. It can also help enhance understanding of the extent of root damage, offering more dependable data.

How to effectively mitigate pythium issues

Proper cultural practices, such as maintaining well-drained soil, avoiding overwatering, and improving soil aeration, can help prevent pythium root dysfunction. Fungicide applications may be necessary in severe cases.

• Choose early morning watering, ensuring deep and spaced-out watering sessions.
• Remove any excessive thatch buildup.
• Avoid excessive nitrogen fertilisation of your turf.
• Encourage better light penetration into your turf.

An effective chemical treatment for pythium

Segway® Fungicide SC offers consistent and rapid control of pythium root dysfunction and pythium blight. The active ingredient in Segway, cyazofamid, stops spores from germinating, inhibiting all stages of pythium fungal development.

Field trials show Segway is highly effective in protecting professionally managed turf areas against pythium diseases throughout a 7 to 28-day period, depending on the level of disease pressure.

Segway Benefits

• Strong control of pythium diseases.
• Registered for control of pythium root dysfunction.
• Unique chemistry, with a unique mode of action. Only fungicides with a Group 21 designation.
• Excellent rainfast properties (within 1 hour). High affinity to the plant cuticle.
• Has translaminar activity – works inside the plant.
• Schedule 5 – Caution – Chemical Scheduling.
• No documented cross-resistance with other fungicides.
• Good rotational tool for pythium management in turf.
• Multiple pack sizes available (500mL and 1L) to suit multiple applications.
• No re-entry or withholding periods when used as directed.
• Demonstrated compatibility with a wide range of fungicides.

Are you curious to know more?

Download the guide now:

Segway is a smart way to get rid of pythium and it can easily be implemented in your Turf program. It can be handy to have it in your shed for instant protection during the Public Holidays! If you need extra help or advice contact us here.