Take-All or Ophiobolus Patch

Gaeumannomyce graminis var. avenae formerly Ophiobolus graminis var. avenae

Disease description
Patches with bleached or bronzed margins develop in turf of Agrostis spp. The centres are killed and invaded by broadleaved weeds and other grasses. Grass in patch margins has little root hold. Small, beaked black fungal structures develop at base of shoots in fall. Patches progress in size from 5 cm to 1 m or more in diameter and persist for several seasons. The disease causes serious problems in British Columbia especially on new turf formed on forest or sandy soils. May also be present in eastern Canada since it is present in eastern U.S.A.

Predisposing factors

while many grasses are attacked, Agrostis spp. are most severely damaged
most common in higher rainfall areas following applications of lime or other alkaline-tending materials which raise the pH of turf surface and upset the microbial balance of the soil
chemical soil sterlization or use of a wide-spectrum fungicide may inhibit antagonistic organisms and allow G.graminis to develop with little check

Cultural control
Where the disease is likely to occur, especially on Agrostis turf, use an acid-tending top dressing such as ammonium sulphate. Acid materials are usually not necessary on new turf on forest soils in British Columbia. Should soil become too acidic (below pH 5, on samples from the top 2.5 to 5 cm) lime may be needed. Use coarsely ground limestone or shell sand in moderate amounts, based on soil analyses, followed by ammonium sulphate or sulphur to re-acidify the turf surface. Renovate diseased patches with resistant or more tolerant grass species such as fescues or blue grasses.

Chemical control
No fungicide registered in Canada or recommended. Avoid wide-spectrum fungicides and soil fumigants for other purposes where take-all patch is known to be a problem since they may hinder the activities of natural soil antagonists. Applications of sulphur will hasten the re-acidifying process.

For information about other diseases that affect turf grasses, go to Major Diseases of Turf Grasses in Western Canada.

For more information about the content of this document, contact Ron Howard.
This document is maintained by Shelley Barkley.
This information published to the web on June 4, 2001.
Last Reviewed/Revised on November 7, 2007.