Helminthosporium Disease

All turf species

• Helminthosporium symptoms can vary.
• Initial symptoms are small lesions on leaf blades.
• Leaf tissues turn yellow around these lesions.
• Severely infected leaves may die and appear light tan to straw-coloured.
• In Couch, Helminthosporium causes dark brown or white "net" blotches on the leaves.
• Young seedlings may be killed by the disease, but mature plants will usually overcome the damage during favourable growing periods.

• Helminthosponum is able to develop at temperatures between 3°C and 30°C.
• Leaf moisture is necessary for infection to occur.
• More than 10 hours a day of leaf wetness for several consecutive days.
• Poor air movement (high humidity in the micro-climate).
• Excessive nitrogen fertiliser.
• Any stress situation such as drought, herbicide injury or heavy traffic can increase the severity of the disease.

• Maintain healthy turf through proper fertilisation. Pay particular attention to potassium and nitrogen levels.
• Irrigate infrequently and deeply.
• Avoid late afternoon or evening irrigations.
• Do not allow the turf to become extremely dry during warm weather.
• Increase air movement and improve turf drainage.
• Avoid herbicide applications during critical periods of disease activity.
• Disperse traffic in high traffic areas.
• Mow turf at recommended height for turf species.

Helminthosporium is a complex of diseases previously known as Helminthosporium leaf, crown and root disease.