Species category: Leaf & Stem Diseases
Scientific name: Drechslera spp / Bipolaris spp / Exserohilum spp.
What is Helminthosporium?
Helminthosporium is a fungal disease that occurs on all turf grass species. The disease known as black helminthosporium happens during warm, moist periods. It causes reddish-brown to purplish-black spots on leaves and stems, and spreads very quickly.
The symptoms vary according to the pathogen. Helminthosporium leaf spot of Kikuyu caused by Bipolaris Australianises starts as small dark brown circular spots.
When does Helminthosporium occur?
These pathogens are active at all times with the ability to develop at a very wide range of temperatures between 3-30°C. Moisture on the leaf surface is necessary to activate the spores and for infection to occur.
Late afternoon or evening irrigation, reduced air movement and overcast days are ideal for leaf infections. Generally, the disease will be most prevalent during mild, wet periods and is more common during autumn and winter.
What damage or effect will Helminthosporium have?
Infected blades of grass eventually wither and die. Severe infestation will lead to turf thinning and eventual death. The loss of grass cover disrupts the playing surface and can break ball roll.