Tech Notes Issue 13
With Spring Quickly Approaching Conditions
Become Favorable for Take-All
Take-all patch is a potentially serious disease of creeping bentgrass turf less than 10 years old. In contrast Poa annua is resistant to Take-all patch. The pathogen, Gaeumannomyces graminis var. avenae infects the roots of creeping bentgrass during cool wet periods of spring. The disease is most apparent during periods of hot dry weather. Symptoms appear as circular patches ranging from a few centimeters in diameter (initial infection) to 1 meter in diameter. The patches are a reddish-brown to orange-brown color. Often times these patches will eventually be colonized by weeds.
Take-all as previously mentioned occurs on newly established creeping bentgrass turf on low organic matter, high pH sandy soils or rootzone mixes. The severity of the symptoms, in general are most severe within the first 3 to 5 years, decreasing in severity beyond this time.
Symptoms of Take-all
(Above left) Early spring symptoms of Take-all on a newly stablished creeping bentgrass tee. (Centre)Take-all symptoms under adequate moisture. (Above right) Take-all symptoms under moisture stress.
Cultural Practices
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If soil pH is high (> 6.5) gradually try to reduce the pH through the use of acidifying fertilizers.
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If possible, minimize the use of alkaline topdressing materials.
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Maintain a balanced soil fertility level. Manganese deficiency can greatly
enhance take-all patch.
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Minimize moisture stress to the infectedarea. Moisture stress enhances
the expression of symptoms.
Chemically
Fungicides are available that can suppress symptom expression. The fungicides that have shown good activity on Take-all include a few of the DMI (demethylase inhibitors) products and one of the strobilurins. The effectiveness of the fungicide treatments is based on timing. Check local fungicide labels for registered use.The fungicides should be applied when the pathogen is infecting roots, normally in early to mid-spring. Applications should be made as a drench treatment, which should be in excess of 800 litres of water per hectares.