You Are Here: Management Updates 2007 Archive May 4, 2007

Date: May 4, 2007
Category: Diseases
Subject: Basal Rot Anthracnose

With the arrival of spring, the UMass Extension Plant Diagnostic Lab is beginning to see numerous cases of basal rot anthracnose. This is not surprising as the disease is exacerbated by stress and the recent, unusual weather of cold, torrential rains followed by sunny, low humidity, windy days has not provided ideal growing conditions for any crops.

Anthracnose basal rot is caused by Colletotrichum graminicola. The fungus survives as a saprophyte in plant debris or as a pathogen in infected tissue and attacks turf growing under low fertility, temperature stress, or both. C. graminicola usually infects grass blades from the tip down, especially freshly mowed grass and can be present on the leaves, roots, or stolons. Symptoms include wilting, yellowing, and brown irregular patches. The disease is most severe in areas of poor drainage, heavy traffic, and soil compaction.

Basal rot can be extremely difficult to suppress when it becomes a chronic problem on annual bluegrass greens. Increase mowing height, divert traffic from affected areas, and avoid potentially abrasive grooming practices such as double-cutting, aeration, and brushing. Anthracnose can be managed with light nitrogen applications and fungicide applications. For curative sprays, always include a high rate of chlorothalonil in the mixture. Tank mix with azoxystrobin (Heritage™), fenarimol (Rubigan™), propiconazole (Banner™), or Al-phosphonate (Signature™). Be sure to water in the systemic fungicides so that they can reach the plant crowns. Greens should be spoon-fed weekly with nitrogen to encourage the growth and spread of healthy bentgrass.

Submitted by: M. Bess Dicklow

DISCLAIMER - As always, it is the responsibility of the applicator to verify the registration status of any pesticide BEFORE applying it. Different states have different regulations as well. The author and the University of Massachusetts are not liable for any consequences of any pesticide "recommendations". Mention of any trade name is not to be considered endorsement of a product.

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