Black or White Helminthosporium (Black or White Helmo)
Black or White Helminthosporium (Helmo) is a common black or white leaf spot disease which is actually caused by Drechslera, Curvulari, Bipolaris and Exserohilum species of fungi. The disease cycle is generally short, as it requires extended periods of leaf wetness to develop and survive.
‘Helmo’ is caused by a common and serious group of diseases, attacking a diverse range of warm and cool season turf grasses. ‘Helmo’ can severely reduce the aesthetic appeal of the turf grass and can lead to the need for turf replacement.
Helminthosporium can attack turf under a wide range of temperatures between 3°C and 30°C, with an optimum range between 15°C and 18°C. It favours high humidity and thrives under conditions of extended wetness in the leaf canopy.
The symptoms of ‘Helmo’ turf diseases vary, depending upon the specific pathogen, grass species, weather conditions, and cultural conditions involved. In general ‘Helmo’ produces small dark or white spots or patches of dead or dying grass (melting out). Leaf tissues turn yellow around these lesions and in severe cases the infected plant dies. Helminthosporium disease is distributed throughout a wide range of climatic conditions.