In The Field: August 6, 2007
After a relatively easy summer so far, the last two weeks have shown many turfgrass managers why this is such a stressful profession. A number of turfgrass disease samples were brought into the diagnostic lab in the past few days. In almost every case, the problem appears to be less related to disease issues (although Pythium may be present) and more an indication of the poor growing conditions on individual greens. The general thinning experienced throughout the region is almost always prevalent on push-up putting greens grown in areas with poor morning sunlight and limited air movement. To exacerbate the problem, drainage is limited to old aerification holes filled with sand, but no internal drainage. As you can imagine, this combination is a recipe for disaster. Unfortunately, although poor growing conditions are the obvious cause of the problem, golf course superintendents are given little help in correcting the underlying problems. Thus, the problems will continue to be seen in subsequent years. Below are a few things that will likely assist in improving the overall health of putting greens grown in a poor growing environment.
The most obvious solution is to improve the growing environment by improving air movement and sunlight penetration. This is often accomplished by selectively removing problematic trees and underbrush surrounding pocketed greens. While this is often the most controversial solution, it is one of the quickest and easiest ways to improve chronic problems with pocketed putting greens. In addition to tree removal, the addition of portable fans can drastically improve air circulation. It is important to note that these fans need to be as large and as close to the putting surface as possible. Although seen as a distraction by some golfers, the ability to putt on healthy greens usually wins out when compared to putting on dirt. Finally, another factor is the poor drainage on putting greens. In a recent Tee to Green
article, I mentioned some of the problems associated with push-up greens in the Northeast. Although topdressing has resulted in a buildup of sand and improved infiltration, the lack of internal drainage leaves the water at the soil-sand interface and limits its movement from the putting green. Various companies now offer a quick solution to the problem by installing internal drainage in older greens with little to no disruption to the putting surface. Taking action this year by removing problematic trees, improving air circulation and installing internal drainage should quickly result in a more durable and healthier putting surface.
In The Field: July 20, 2007
A cornucopia of diseases are being found in the field right now. This includes bacterial wilt, Pythium blight, summer patch, brown patch, anthracnose, dollar spot and others. Another malady of perennial ryegrass and in some cases creeping bentgrass has been the presence of etiolated plants. The problem, commonly referred to as Etiolated Tiller Syndrome (ETS) or Mad Tiller Disease has been showing up throughout the region following all of the heavy rains. The cause of the problem is unknown, but many theories have been suggested including bacterial wilt and a Fusarium species that produces gibberellic acid. Some superintendents have associated the symptoms with applications of certain plant growth regulators, but symptoms have been found this year on golf courses not using PGRs. Check out the photo
by Steve McDonald of Turfgrass Disease Solutions in the Philadelphia area to see what ETS looks like.
Bacterial wilt, the most alarming of the diseases due to the lack of control options has begun to appear on at least a couple of golf course putting greens in CT. Although a few products are labeled for the control of bacterial wilt, few if any provide real suppression of the disease. Cultural practices should be adjusted to avoid severe outbreaks. These include mowing affected greens with a dedicated walk-mower and disinfesting the mowers with a 10% bleach solution. Mowing should also be done in the afternoon when the turf is dry if possible. The bacterial pathogen can only gain access into the plant through wounds and mowing during the early morning hours when the disease may be present can increase the problem. For this reason, other cultural practices that cause injury such as topdressing and vertical mowing should be ceased until disease symptoms are no longer present. Finally, every effort should be made to keep the greens as dry as possible. For more information on bacterial wilt, visit our factsheets at http://www.turf.uconn.edu/factsheets.shtml
In The Field: June 30, 2007
Our first week of HOT weather departed as quickly as it arrived. Recent samples arriving into the diagnostic center varied depending on the location in New England. In Maine, brown ring patch is still active and causing minor problems for some superintendents. In the extreme southern portions of New England and parts of New York, fairy ring is beginning to appear and the hot weather diseases have made a brief appearance.
Diseases such as Pythium blight and brown patch caused by Rhizoctonia zeae
are beginning to develop. No reports of the traditional brown patch have been reported in our lab, but for those of you in the warmer parts of New England, July 4th is usually the time to look out for this disease. Very few cases of summer patch have been reported, but disease incidence is increasing. Anthracnose seems to be in limbo right now as those courses dealing with the early season type of the disease are seeing recovery, while those who traditionally see damage during the summer months are still waiting for the disease to begin.
The major concerns throughout the region are the apparent record numbers of annual bluegrass weevils. According to UMASS entomologist Pat Vittum, "We have seen the highest populations in at least 20 years on virtually every golf course in the Northeast." Click here
to read Dr. Vittum's latest insect report...it sounds like it could be a long summer for these pests.
Dollar spot continues to be severe throughout the Northeast and the mild temperatures forecasted for much of early July should make collecting those dollar spot samples for UConn's Dollar Spot Resistance research a snap. If you don't have any dollar spot, please help us by putting down a small (6" x 6") board on a portion of your putting green and fairway prior to your next spray.
In The Field: June 21, 2007
Based on samples arriving to the lab this week, Pythium blight, brown patch (caused by Rhizoctonia zeae), and anthracnose are active throughout the region. These diseases can cause severe damage in a relatively short period of time, so preventive applications of an effective fungicide are warranted. Caution should be used when treating for R. zeae as some traditional brown patch fungicides (e.g., thiophanate-methyl) may be ineffective.
Although less widespread than in recent years, anthracnose basal rot has caused significiant damage to select golf courses in the region. Fungicide trials over the last two years at courses in Greenwich, CT have revealed considerable differences in fungicide efficacy. Results of these two studies suggest that selecting an effective fungicide for your course will take some local knowledge. While the QoI's tested in 2006 provided little to no control, they provided the greatest level of suppression in the 2007 study. The two studies were conducted on golf courses only a couple of miles apart.
Finally, remember to assist us in our dollar spot research by sending in dollar spot samples from putting greens and fairways. If dollar spot is not appearing on your course, go the extra step and place a small board (6" x 6") on the back of your putting green or fairway prior to your next spray. Results of this study will assist in determing the level and type of fungicide resistance prevalent in New England.
In The Field: June 1, 2007
Disease-related problems have been few due to the lack of rain that we have received throughout the region. In some regions, dollar spot has started to appear. Early season applications of fungicides for dollar spot control, however, still appear to be holding up well.
The few disease issues that we have seen throughout the region include anthracnose basal rot, dollar spot, brown ring patch, and continued cases of fairy ring. We are several weeks away from seeing outbreaks of brown patch and other summer diseases.
Although diseases have been kept to a minimum, weeds are hitting their stride. Crabgrass has germinated throughout the region and in many cases have grown too large for early post-emergence control. Yellow nutsedge has also been seen in the Southwestern portion of Connecticut and probably is starting to germinate in regions farther north as well.