Drechslera spp., Bipolaris spp. and Exserohilum spp.

Other common names:

Helminthosporium.

Description:

Helmo, formerly Helminthosporium spp. are a common and serious group of diseases, including Drechslera spp., Bipolaris spp. and Exserohilum spp., that can severely reduce the aesthetic appeal of the turfgrass or in severe cases can lead to the need for turf replacement to occur. The disease is able to develop at temperatures between 3°C and 30°C, with favourable temps being between 15°C and 18°C. The disease cycle is generally short requiring extended periods of leaf wetness to develop and survive.

Susceptible Turf:

Warm-and cool-season turfgrasses across Australia.

Symptoms:

The symptoms of helmo turf diseases vary, depending upon the specific pathogen, grass species, weather conditions, and cultural conditions involved. In general, white helmo produces small bleached (white) spots or patches of dead of dying grass which do not measure more than about 10 cm in diameter (Wong, 2010). Black helmo is the same as the latter with the exception of producing black spots or patches and “melting out”. Leaf tissues turn yellow around these lesions and in severe cases the infected plant dies.

Control options:

• Pesticides: See available tabs below for registered products. Use as per label instructions.
• Integrated Pest Management (IPM): Use a combination of approaches listed on this page.
• Cultural:
  • Maintain turf density and nutrition to at least and acceptable standard.
  • Improve drainage and airflow within the soil profile.
  • Frequent, shallow watering should be avoided; so too late afternoon or in the evenings so water does not sit on the least or within the turf canopy.
  • Reduce thatch levels within the turfgrass.
  • Mancozeb may be sufficient if the disease is identified early.
  • Following mowing of turfgrass affected by helmo and other noticeable diseases, it is recommended that the clippings be captured (not returned) and destroyed.
• Mechanical: Nil.

References:

Wong, P. (2010) New patch diseases of couch in Australia, 26th Annual Australian Turfgrass Conference Proceedings, Gold Coast, pp. 58-61.

Disclaimer:

Turf Finder or its developer accepts with no responsibility for any consequences whatsoever resulting from the use of any information or product(s) listed herein. Products are to be applied as per label instructions.