You Are Here: Management Updates 1998 Archive July 29, 1998

Date: July 29, 1998
Category: Diseases
Subject: Summer Patch, Anthracnose, Fairy Ring

Turf diseases are less prevalent this week because the humidity is less and, unfortunately, most places have not had much rainfall. Drought dormancy is common in non-irrigated turf, notably in circles around the bases of trees due to water competition. Even people with automated watering systems are probably having trouble getting enough water to lawns. It is important to check with a soil probe or shovel to determine if enough water has been applied to reach 4-6" into the soil. Avoid night time watering in hot weather which can result in brown patch and, less frequently, Pythium blight. Water in the early morning hours (after 3 a.m.) when possible.

On golf courses, summer patch and anthracnose continue to progress, particularly in annual bluegrass (Poa annua). Yellowing symptoms are most common on small greens where traffic stresses the turf. The clean-up pass is another area susceptible to stress at this time of year. Where possible, consider skipping this final extra mowing for a few days to allow the turf to recover from the past couple of stressful weeks. Many courses have sponsored tournaments in these weeks which require extra mowings and extra golfers. A temporary raising of mowing height can go a long way to help turf recover.

Many golf course superintendents are reporting fairy rings. Most reports are of extra green rings without turf injury. Keep in mind that the fungi that cause fairy rings are saprophytes that get their nutrients from dead organic matter and do not attack turf directly. In the process of degrading organic matter, nitrogen is released which fertilizes the turf resulting in the green ring. In most cases, golfers do not complain about green grass! Fairy ring occurrence varies a lot from week to week and from season to season. It is often associated with excess thatch, but can also occur in sand-based greens. If the extra green ring is the only symptom, try masking it with iron. Make sure the surrounding turf is getting enough water and fertilizer so the ring is not so obvious. The main concern is that the soil near the ring may become hydrophobic. Spiking, wetting agents, hydroject, aeration all may help avoid turf injury. Flutolanil (ProStar) is the only fungicide labelled for fairy ring. Results have been very mixed. Cultural approaches will probably be more effective.

- Submitted by: Dr. Gail Schumann