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TURF TALK Kate York Plant Pathologist PATHOLOGY ROUND UP TURF DOCTOR'S NOTES G J2 Close-up of Thatch Fungus This has been a great summer for turfgrass diseases - depending on your point of view of course! The laboratory has been busy not only with the more common summer diseases but, in addition, one or two ratherunusual problems have also been identified this year. Firstly, the more common disease prob- lems. Towards the beginning of the sum- mer, I received a large number of samples showing various symptoms of superfi- cial fairy ring activity (thatch fungi). These fungi can cause quite devastating symp- toms on areas of fine turf and can develop at an alarming rate under the right weath- er conditions. In a similar way, the symptoms of red thread disease can decrease the visual quality of the sward quite dramatically. This disease was also prevalent during the early months of the summer. Outbreaks of this disease have left scars on some of the more heavily attacked areas, which are still evident at this late stage in the year. On the trials ground at STRI,some of the plots receiv- ing high nitrogen inputs have been affect- ed by this disease, which is unusual since it is generally noted for its occurrence on areas of low fertility. It does appear, how- ever, that worldwide, wherever red thread occurs, it is now developing on areas which receive relatively high nitro- gen inputs. Another problem which is apparently increasing in incidence is leaf spot. All grasses are susceptible to leaf spot diseases but the causal pathogen is not necessarily the same in each case. Over the summer, leaf spot diseases have developed extensively all areas of high maintenance fine turf, fairways, outfields and lawns. Generally these diseases may slightly affect the overall look of the turf but this year, samples have been received into the lab in which leaf spots have caused severe and extensive damage to the sward. Numerous samples arriving on the laboratory bench with a request for dis- ease analysis, have ultimately turned out to be problems of scorch. Symptoms have generally been patches of bleached turf, usually Poa annua, anything from 1 em to 5 em in diameter. It can be extreme- ly difficult to identify scorch with quick look over the symptoms, but in the labs it is relatively' straight forward. An initial check is done to ensure that the problem is scorch and that no pathogenic fungi are involved, and a second test can be done to see if the applied product that caused the scorch is still present in the rootzone and needs treatment. Rusts are a group of diseases caused by fungi which are generally not com- monly found on turf in the UK. However, during this summer, several samples have been identified in the laboratory and the disease has also been seen on the STRI trials ground as well. In one extreme case, a greenkeeper informed us that the problem was so bad on his fairway that the spores formed a cloud around the mower and collected as an appreciable layer on the machine deck. One of the more interesting requests received this summer was from a bowl- ing green. The Groundsman had telephoned with a request for us to iden- tify the' caviar' that had appeared on the green. After lengthy discussion with one of our advisory staff, the Groundsman decided to send in a sample for analysis, since none of the suggested possible causes for the, problem I sounded right'. Once the sample arrived, I fully under- stood why there had been difficulty in assisting the Groundsman over the TURFGRASS BULLETIN ISSUE 198 33 TURF TALK This Summer Leaf spot diseases have developed extensively in all areas of high maintenance fine turf, fairways, outfields and lawns. -How to discourage unwelcome visitors President & Chief Scientists of the u.s. International Sports Turf Institute Inc. James B Beard A few geese are a nice wildlife feature on turfed golf courses and parks. These few may attractmore geese, until the numbers exceed the capacity of the site. Defoliation of the green cover and coverage of the soil with excre- ment become serious problems. Pratical experi- ence in the field is now accumlating concerning relative success and failures of various methods to discourage excessive numbers of geese on turf areas such as golf courses and parks. The irritant sprays that have been developed require frequent reapplication, and are quite expensive. To date they havenot been used to any significant extent. The method of using trip wires along the water's edge is quite costly and has some limitations. The method that seems to be achieving the most success is the use of a dog to herd the geese off the turf area onto adjacent water areas. Using this approach at 30 minute intervals continuously throughout consecutive days eventually result in significant success. The geese eventually get tired of the disturbance and move on to more quiet sites. It may take from 8 to 14days of continu- ous discruption of their feeding pattern on the turfgrass areas until the geese depart. The procedure may need to be repaired occasionally as visiting geese test a potential new habitat site. The key to success is a properly trained dog and a persistent effort. This article first appeared in TURFAX, Volume Number 2, an International Newsletter reporting on current developments in Turfgrass. The newsletter is published by the International Sports Turf Institute in Texas, USA. Further details can be obtained by contacting them direct on fax number 409-693-4878. identification. The fungus, Curvularia spp. is not uncom- mon in soils in this country, but its dramatic and devastat- ing effect on the sward in this case,was alarming. Of course, there are n~ pesticides which have approval for use against this disease! On a slightly different note, my summer was made by a brief visit from Dr Noel Jackson who is currently working at the University of Rhode Island, America. It was the first time that I had had the pleasure of meeting Noel and it was great to be able to chat about diseases to some- one who knows! He worked at STRI between 1957 and 1965 as the plant pathologist and was co-author (with Drew Smith and Roy Woolhouse, both past-STRI pathologists) of my 'bible' - Fungal Diseases of Amenity Turf Grasses. Drew has made a couple of visits to STR! since I started working here and Roy has been a regular visitor over the years. So now the trio is com- plete. As long as everything goes wellwith his knee opera- tion(s), Noel will be returning to STRI next year on a few months sabbatical. I wish him all the best and look forward to seeing him again. telephone. The 'caviar' was found to be the blue-green algae Nostoc. Each of the 'beads of caviar' was a colony of the algae which contained numerous individual fila- ments. This is not a frequent find on turf although different algae are commonly seen on areas of low turf cover, shaded areas and areas which remain relatively wet on the surface for extended periods. The most interesting find of the summer for me has to be the identification of Curvularia disease on a cou- ple of the greens and sur- rounds of a golf course in Surrey. The affected patches in the sward had been described as having occurred after 24 hours of heavy rain and high humidity. The patches appeared at first in small sometimes irregular circles, quickly joining to form large unusual and irregular shapes. The disease devel- oped rapidly; in less than 48 hours. The problem could not be identified at first because,. by the time the sample arrived at the labs, the turf had been colonised by fungi that cause decomposition. A second batch of samples, collected at the very first sign of disease, allowed for successful 34 TURFGRASS BULLETIN ISSUE 198
