You Are Here: Management Updates 2005 Archive May 25, 2005

Date: May 25, 2005
Category: Diseases
Subject: Cool Spring Diseases

The Turfgrass Disease Diagnostic Lab is seeing a lot of cool weather diseases that normally would not be active at the end of May including yellow patch (Rhizoctonia cerealis), cool-season Pythium root rot, and the patch diseases caused by ectotrophic root infecting fungi - take-all patch (Gaeumannomyces graminis) and necrotic ring-spot (Leptosphaeria korrae). The patch diseases are active in the cool, wet weather of spring and fall, although the symptoms of wilting and patch development are not seen until the summer stress period. Take-all is most serious on newly established bentgrass greens and an application of Heritage™ is warranted if the infection is severe. Yellow patch or cool weather Rhizoctonia probably can't be controlled at this time with fungicide applications and the disease activity will cease with warmer temperatures. Pythium root rot can only be controlled by fungicides specific for the 'lower fungi" or water molds such as Subdue™ or Alliette™.

Many superintendents are reporting off-color and unresponsive turf; this may be more a function of the unseasonably cool weather than a specific disease problem.

Submitted by: M. Bess Dicklow
UMass Extension Plant Diagnostic Labs

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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