You Are Here: Management Updates 1999 Archive July 12, 1999

Date: July 12, 1999
Category: Diseases
Subject: Summer Diseases, Poa Decline

It's hard to know what to write the week following such extreme environmental stress combined with a high-volume holiday weekend. The good news is that things are better, the nights are cooler, and it looks like it will be like this for at least a few more days.

The high temperatures, rainfall, and high humidity were the perfect recipe for fungal diseases and most people saw them no matter what kind of turf they manage: BROWN PATCH, DOLLAR SPOT, some scattered PYTHIUM BLIGHT. ANTHRACNOSE took out turf on some golf courses. There are NO reports of GRAY LEAF SPOT of perennial ryegrass yet. The good news is that night temperatures in the 50s mean the end of Pythium blight and brown patch. This is nature's fungicide. In lawns and on golf courses, brown patch rarely kills plants. The relatively good weather conditions favor recovery from all problems.

SPECIAL NOTE ON DECLINING POA ANNUA:
A number of golf courses have areas where the Poa annua (annual bluegrass) took a turn for the worse on Tuesday (July 6) following the holiday weekend. Poa in areas recently filled in from last winter's ice damage appeared to be most vulnerable. In the samples I saw, these plants had shallow roots which would have been subjected to a lot of heat stress. It may be that the weekend stress followed by a lot of dry air on Tuesday was just enough to push them over the edge even though it was cooler.

Reports and samples from late this week show that the decline is continuing in many areas still without an obvious fungal disease. The samples tend to be very uniform. In fact, samples from several sites in CT and NY look almost identical. This all points to environmental stress as the cause. Many plants remain alive in the centers, and could recover. Try to baby them along and hope the cooler weather and rain continue.

- Submitted by: Dr. Gail Schumann