You Are Here: Management Updates 2003 Archive July 18, 2003

Date: July 18, 2003
Category: Diseases
Subject: Anthracnose, Summer Patch, Take-All Patch, Bacterial Wilt

The moderate weather this week has been a real help to turf managers, but many of the diseases that began with the past heat stress have continued. Anthracnose (mostly Poa annua, some bentgrass), summer patch (Poa annua) , and take-all patch (bentgrass) affect roots and crowns. Even with chemical control, recovery can be slow. Bacterial wilt was diagnosed on Poa annua in a putting green with a very poor root environment. Several samples of young bentgrass had shredded leaves and a reddish color from mechanical injury from mowing in hot weather and especially on wet turf. Recovery from this kind of heat stress injury can also be slow. It is important to try to aerate and create a deeper root system that can better tolerate hot spells. See Dr. Peter Dernoeden’s excellent book “Creeping Bentgrass Management” (Ann Arbor Press) for photos and more detailed discussion. The hot weather also demonstrated how vulnerable Poa annua can be when it has a shallow root system. Some samples had healthy roots, but the plants still collapsed from drought and secondary fungi moved in. Be cautious in cooler days with very dry air. Plants with impaired roots from disease and/or shallow growth need frequent syringing to keep them alive and growing. In the long run, a deeper root system will be more tolerant of the occasional hot spell.

The UMass Turf Disease Diagnostic Lab will be open all of next week (July 21-25), but Dr. Schumann will be out of the office for some of the time because the moving van is coming. However, samples will be diagnosed on the day of arrival. She will be flying out to Milwaukee on Friday afternoon to help unpack, so please try to avoid samples on Friday, July 25. She will return on Monday, July 28.

There will be no disease message next week because our webmaster will be on a well-deserved vacation. Luckily, it looks like another moderate weather week coming up.

- Submitted by: Dr. Gail Schumann