August 28th, 2013
With the Iowa temperatures expected to continue in the upper
90’s with high humidity for the foreseeable future, it presents conditions
conducive to Pythium blight activity. Pythium is known as one of the most
destructive turf diseases in the Midwest and overnight it can lead to large
turf death. With most turf managers fungicide programs winding down for the
year; it might be the time to have a bottle of Cyazofamid (Segway®) handy for a
knockdown contact application.
Pythium is a high temperature disease which presents the
most damage under daytime temps in excess of 86⁰F, followed by nights in the high 60's. It
usually affects close-mown turfgrass under intense management. Symptoms
generally include small circular patches (1-2 inches) accompanied with a
cotton-like mycelia that appears in the early morning. Pythium is often first
noticed on sites with poor drainage. It is also easily spread by
mechanical means and can be carried over turf by foot traffic and/or mowing
equipment. Reducing your nitrogen
fertility inputs, avoiding night watering, increasing air movement, and
improving areas with poor drainage reduces your threat for disease
incidence.
Below are some pictures of the cotton-like mycelia seen in the early morning.