Take‑All Patch (Gaeumannomyces Graminis / Ophiobolus)
What Is It?
Take-all Patch is a fungal disease that attacks the roots and crowns of plants, causing turf to die in a circular pattern.
Have I Got It?
The name ‘patch’ disease is used because of the symptoms experienced when Take-all is present. It is primarily a problem on bent grass including the modern creeping bent cultivars. Most often found in new constructions where rootzone with a high percentage of sand has been used. Early symptoms are usually small depressed circular patches; as the disease matures these may expand to 18-inch diameter. The turf in the patch is a light straw colour and when it is active the outer edge may have a bronze appearance similar to Fusarium.
Resistant grasses and weeds may grow in the centre of the patch; sometimes this is referred to as “the frog eye appearance”.
If I Have Got It How Do I Try To Control It?
Take-all patch is not easy to control. As in all cases with turf try to promote good rooting, so fertilize with a root development product such as Mascot Activate ‘R’ . Avoid using anything alkaline, so top dressing should be carefully chosen. Ensure there are sufficient levels of phosphorus, potash, magnesium, manganese, copper and zinc. Use fertilizer with a nitrogen source of ammonium sulphate and try to reduce the pH to 5:5.
Azoxystrobin is the only UK approved active ingredient for the control of Take-all Patch. Panama contains Azoxystrobin and is best applied April to October.
How Do I Try To Prevent Re-Occurrence?
In new constructions antibodies will gradually increase and naturally control the disease. In established turf avoid alkaline dressings, either fertilizer or top dressing.
Check the pH if the disease persists and try to acidify the profile to at least the depth of the roots.
When this disease is seen in turf which has been down for a number of years, it is usually caused by applications of calcium carbonate.