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Fungal diseases of sports turf
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FUNGAL DISEASES OF SPORTS TURF N A BALDWIN The Sports Turf Research Institute, Bingley, West Yorkshire, BD16 lAU The Sports Turf Research Institute (STRI) was established in 1929 under the title 'Board of Greenkeeping Research' to provide a research and advisory service for golf clubs in the British .Isles. Reconstitution as the STRI in 1951 started the diversification of the Institute to cover all types of sports turf and marked the beginning of nearly 40 years research on the biology and control of turfgrass diseases. This article describes the most common sports turf diseases that occur in the UK which must be controlled to obtain a high quality surface. In the UK, sports turf areas are diverse in their intended use and also very abundant. There are approximately 193,000 hectares of intensively managed amenity turfgrass consisting of, for example, approximately 2,300 cricket pitches, 1,850 golf courses and 35,000 football pitches (Symes, 1987), all of which are prone to disease attack. In contrast to the agricultural situation, where disease severity is determined primarily by reductions in yield, disease impact on sports turf is assessed using two other criteria - aesthetic value and playing quality. The aesthetic value of turf, i.e. visual appearance, is often the major way in which the quality of a sports turf surface is judged by the sportsman. For example, areas of turf which are bleached due to red thread disease or ugly brown scars, the result of an attack by Fusarium Patch Disease (Fig. I), detract greatly from the appearance of fine turf. The playing quality of a sports turf area is more difficult to define, but the term is used generally to describe the performance of the turf surface for the appropriate sport. In this respect, disease is particularly important in sports such as golf where the ball and turf surface closely interact. For example, Take-all Patch Disease (Fig. 2) may thin the sward, kill certain turfgrass species and produce an uneven putting surface on which a true putt is impossible. Conse-
quently, a diseased golf green damaged in this way would be unacceptable to the sportsman. Fusarium Patch Disease (Microdochium nivale (Fr.) Samuels & Hallett, formerly Fusarium nivale) During the winter months, Fusarium Patch Disease is the most common, damaging and disfiguring disease of fine turf (e.g. bowling and golf greens). This disease usually first appears as small (up to 50 nun diameter) orange-brown, water soaked, circular spots (Fig. 1) which, under favourable conditions, may increase rapidly and coalesce together to form large circular spots. Under prolonged humid conditions, sparse white or pink mycelium may be seen around the edges of each patch which tends to mat affected leaves together. If diseased tissue is mounted and examined microscopically abundant, curved conidia (1-3 septa) may be seen to confirm diagnosis (Booth, 1971). Eventually, surface scars are formed which heal slowly in the winter months and are consequently prone to invasion by moss and weeds. As with many host/pathogen situations, an integrated disease management programme has been developed for Fusarium Patch Disease. Good, general turf management will do much to limit the incidence and severity of this disease. Cultural control methods are based on ensuring the turf surface is kept dry, as the disease thrives in wet, humid conditions. Turf is regularly switched (brushed with a flexible fibreglass pole) in the early morning to remove dew, and spiking and slitting operations also aid water movement away from the turf surface. The fescues (Festuea spp) and bents (Agrostis spp) are more resistant to Fusarium Patch than other grass species and general turf management policies are designed specifically to favour these grasses whilst discouraging the disease
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susceptible annual meadow-grass (Poa annual. Even in situations where disease incidence and severity have been limited by cultural means, applications of fungicides are often necessary to achieve satisfactory control. In contrast to the wide range of fungicides available for disease control of agricultural crops, the range of turfgrass fungicides is limited to a few active ingredient groups only. In the spring and summer when the grass is growing, systemic fungicides such as the Benzimidazoles, e.g. carbendazim and thiabendazole, are generally effective. In the winter months when grass growth is slow and Fusarium Patch is often very active, Dicarboximide fungicides, e.g. iprodione and vinclozolin, are preferable as they possess some eradicative properties. Preventative spraying, i.e. making applications before disease symptoms are evident, is generally not recommended as this policy can prove wasteful if, for example, the weather changes and disease does not develop. Curative applications, Le. spraying established disease, are usually ineffective, except repeated applications of Dicarboximide fungicides. In most situations spraying at the first signs of disease development will give the best control of Fusarium Patch Disease. Thread (Laetisaria fuciformis (McAlp.) Burds.) During the summer months Red Thread, or Corticium Disease as it is sometimes known, may be common and disfiguring on fine and coarse (e.g. football pitches) turf. Red Thread has several characteristic symptoms that enable it to be distinguished from other turfgrass diseases. Generally, Red Thread appears as bleached areas 20-50 mm in diameter which may coalesce to form large irregular patches 0.35 m in diameter. Closer examination of affected areas reveals pink mycelium binding together leaf blades, cottony floes of mycelium and red stromata (commonly called needles or threads) as seen in Fig. 3. Although Red Thread may be found on most turfgrasses, the fine-leaved Red
fescues and perennial ryegrass (Lolium perenne) are most susceptible to the disease. Cultivar evaluation trials at STRI are monitored and assessed for severity of Red Thread and recommendations published annually (Anon. 1989). Selection of grass cultivars resistant to Red Thread is an effective disease management strategy. Red Thread is most common under low fertility conditions, particularly where the turf is deficient in nitrogen. as is often the case, for example, on golf course fairways where fertilizer is not normally applied. Football pitches which consist mainly of perennial rye grass are sometimes attacked by Red Thread in early summer when fertilizer applications made in spring have been utilised fully. Consequently, light, frequent fertilizer applications during the growing season will prevent severe attacks of Red Thread by ensuring adequate fertility. However. great care is needed as over-application can produce lush grass susceptible to Fusarium Patch Disease. If fungicides are thought necessary (usually careful cultivar choice and adequate fertilizer will prevent severe Red Thread attacks), then the Benzimidazoles mentioned above are effective. Take-All Patch Disease (Gaeumannomyces graminis (Sacc.) v. Arx & Olivier) Take-all Patch was relatively unknown in turfgrass until the 1950's when it was the practice to correct extremely acidic turf with applications of lime. As liming encourages Take-all (also the case in wheat), many severe outbreaks were recorded. Due to the very destructive nature of Take-all Patch, its persistence and the absence of an effective control measure, it is regarded as a serious problem in turf management. Symptoms of Take-all Patch usually appear in late summer or autumn. On fine turf, the disease often appears initially as saucer-shaped depressed areas consisting of dying bents. which are very susceptible. These small patches may then enlarge into a ring, measuring
18
Fig . 1: A typical scar produced by Fusarium Patch Disease . Not e th e orang elbrown colouralion . Fig . 2 : Stromata (needles or threads) produced by Red Thread . Fig . 3: Extensive damage by Take-all Patch Disease. Not e th e irregular rings of dying bents ex h ibiting an orangelbro wn colour ati on . Fig . 4: Fairy-rin g (Ma ra smius oreades) on a golf fairway.
up to 0 .3 m in diameter, of bleached or bronze bents , the centre of each ring being occupied b y plants resistant to the dis ease, such as fescues , a n nu a l meadow-grass and broad-lea ved weeds. Dying bentgrasses can be easily removed from th e turf, due to their rotted root systems. The roots and rhizomes of affected bents are blackened due to extensive production of runner hyphae, and perithecia may be observed under leaf sheaths at the base of the plant. There are several cultural conditions unique to golf turf that favour the development of Take-all Patch Disease. Firstly, in recent years, all-sand construction methods for golf, where greens are made by establishing a bentgrass monoculture on a pure sand rootzone, have become increasingly popular.
Greens constructed in this way have proved to be prone to th e di sea se , due presumably to th e ab se nce of antagonistic fungi and bacteria in the sand medium a n d rapid disease spread through a highly susceptible bentgrass sward . Secondly , constru ction materials are often sterilised and antagonists consequently reduced . Thirdly , greens are irrigated during dry weather by an automatic sprinkler system. In areas where the supply of water is 'hard', lime may be applied ev ery time watering takes place. Finally , most turf areas have a layer of thatch (partly decomposed grass remains) below th e turf surface which , in situations where Take-all is present, will act as a sub strate for a reservoir of fungal inoculum to surv ive unfavourable conditions during the winter
19 and cause re-infection the next spring. Once Take-all Patch has occurred adequate control is very difficult to achieve. Consequently. all efforts must be aimed at preventing disease outbreaks. Applications of lime should be avoided and sands used in construction or top dressing, and irrigation water should be analysed for its lime content prior to use. The phenomenon of Take-all decline, wetr documented for successive wheat crops, is also used to explain the progressive disappearance of the disease symptoms over several years in fine turf. As Take-all Patch recurs rarely on affected turf areas, natural decline offers a long term solution. Light applications of sulphate of iron (widely used on turf for moss control and improving turf colour) acidify the turf surface and thus partially inhibit the disease. Other Turfgrass Diseases Mature turf is attacked by a wide range of fungal diseases which vary in importance from those that generally only
cause minor damage, e.g. Powdery Mildew (Erysiphe graminis DC), to those that may cause more serious problems, such as Fairy Rings (Marasmius areades (Bolt.: Fr.) Fr.). The establishment of turfgrass seedlings may also be reduced by damping-off fungi attacking at both the pre- and post-emergence stage. A concise gu ide to the common fungal diseases of sports turf may be found in the STRI publication Turfgrass Diseases (Baldwin 1987). REFERENCES ANON (1989). Turfgrass Seed 1989. 12 pp. Sports Turf Research Institute, Bingley, England. BALDWIN. N A (El87). Turfgrass Diseases. 40 pp. Sports Turf Research Institute, Bingley, England. BOOTH. C (1971). The Genus Fusarium. 237 pp. Commonwealth Agricultural Bureaux, Kew, England. SYMES. B M C (1987). A Research Study and Review of Intensively Managed Amenity Turfgrass in the UK. Special report No.2. 40 pp. National Turfgrass Council, Bingley, England.
THE BERKELEY A WARD OF THE BRITISH MYCOLOGICAL SOCIETY T he Ber kel ey Aw ard , whi ch com me mora tes the co ntribu tio ns of th e Rev M J Berkeley (180 :1-1889) to myco logy, is mad e a n n ually a nd nomina ti ons are inv ited for 1!l!)0. The Candida te shou ld nor ma lly be und er :15 yrs on th e 1s t of Ja n ua ry of the Award year. Alt ho ug h the Ca ndi date need not b e a BMS Membe r, th e nom ination shall be proposed a nd secon ded by two Me m bers . A Cand ida te may be nom ina ted o n more tha n one occas io n bu t may o n ly rece ive a n A ward o nce . T he Award co nsists o f the Be rkel ey Cita tio n of the Society, toget he r wi th a s u m of £5 00 for use in furth er resea rch (in cluding boo ks a nd tra vel ), It wi ll be assessed on the bas is of ev ide nce of ou ts ta n d ing orig inal sc ie ntific co ntri bution wit h in any area of m ycol ogy , a n d may be s u p po rte d by p ub lish ed papers . T he co ntri butio n need not h av e been u nd e rtak en in th e Un ited Kingdo m. Nom inatio ns, w it h ev ide nce of th e work o n whi ch it is based , s ho u ld be sent by the nominators to the Ge ne ra l Sec retary . T he ev ide nce s ha ll co ns is t of a Curricu lum v ita e , an d a s u m ma ry of th e co n trib u tio ns mad e to m ycol ogy . In addi tion a co nc ise stateme nt of s u p p ort is al so re queste d. The closing date for n ominations is 31 March 1990. Th e A wa rd w ill be p rese n te d at th e Soci ety's Ann ua l Ge neral Meet in g in December. The recipie n t will be in v ited to d eliver a lect ure on h is/h er w ork at a s ubseq uen t scie n ti fic meeting , a nd this w ill be p ub lished in Myco logi co] Research .
FUNGAL DISEASES OF SPORTS TURF N A BALDWIN The Sports Turf Research Institute, Bingley, West Yorkshire, BD16 lAU The Sports Turf Research Institute (STRI) was established in 1929 under the title 'Board of Greenkeeping Research' to provide a research and advisory service for golf clubs in the British .Isles. Reconstitution as the STRI in 1951 started the diversification of the Institute to cover all types of sports turf and marked the beginning of nearly 40 years research on the biology and control of turfgrass diseases. This article describes the most common sports turf diseases that occur in the UK which must be controlled to obtain a high quality surface. In the UK, sports turf areas are diverse in their intended use and also very abundant. There are approximately 193,000 hectares of intensively managed amenity turfgrass consisting of, for example, approximately 2,300 cricket pitches, 1,850 golf courses and 35,000 football pitches (Symes, 1987), all of which are prone to disease attack. In contrast to the agricultural situation, where disease severity is determined primarily by reductions in yield, disease impact on sports turf is assessed using two other criteria - aesthetic value and playing quality. The aesthetic value of turf, i.e. visual appearance, is often the major way in which the quality of a sports turf surface is judged by the sportsman. For example, areas of turf which are bleached due to red thread disease or ugly brown scars, the result of an attack by Fusarium Patch Disease (Fig. I), detract greatly from the appearance of fine turf. The playing quality of a sports turf area is more difficult to define, but the term is used generally to describe the performance of the turf surface for the appropriate sport. In this respect, disease is particularly important in sports such as golf where the ball and turf surface closely interact. For example, Take-all Patch Disease (Fig. 2) may thin the sward, kill certain turfgrass species and produce an uneven putting surface on which a true putt is impossible. Conse-
quently, a diseased golf green damaged in this way would be unacceptable to the sportsman. Fusarium Patch Disease (Microdochium nivale (Fr.) Samuels & Hallett, formerly Fusarium nivale) During the winter months, Fusarium Patch Disease is the most common, damaging and disfiguring disease of fine turf (e.g. bowling and golf greens). This disease usually first appears as small (up to 50 nun diameter) orange-brown, water soaked, circular spots (Fig. 1) which, under favourable conditions, may increase rapidly and coalesce together to form large circular spots. Under prolonged humid conditions, sparse white or pink mycelium may be seen around the edges of each patch which tends to mat affected leaves together. If diseased tissue is mounted and examined microscopically abundant, curved conidia (1-3 septa) may be seen to confirm diagnosis (Booth, 1971). Eventually, surface scars are formed which heal slowly in the winter months and are consequently prone to invasion by moss and weeds. As with many host/pathogen situations, an integrated disease management programme has been developed for Fusarium Patch Disease. Good, general turf management will do much to limit the incidence and severity of this disease. Cultural control methods are based on ensuring the turf surface is kept dry, as the disease thrives in wet, humid conditions. Turf is regularly switched (brushed with a flexible fibreglass pole) in the early morning to remove dew, and spiking and slitting operations also aid water movement away from the turf surface. The fescues (Festuea spp) and bents (Agrostis spp) are more resistant to Fusarium Patch than other grass species and general turf management policies are designed specifically to favour these grasses whilst discouraging the disease
17
susceptible annual meadow-grass (Poa annual. Even in situations where disease incidence and severity have been limited by cultural means, applications of fungicides are often necessary to achieve satisfactory control. In contrast to the wide range of fungicides available for disease control of agricultural crops, the range of turfgrass fungicides is limited to a few active ingredient groups only. In the spring and summer when the grass is growing, systemic fungicides such as the Benzimidazoles, e.g. carbendazim and thiabendazole, are generally effective. In the winter months when grass growth is slow and Fusarium Patch is often very active, Dicarboximide fungicides, e.g. iprodione and vinclozolin, are preferable as they possess some eradicative properties. Preventative spraying, i.e. making applications before disease symptoms are evident, is generally not recommended as this policy can prove wasteful if, for example, the weather changes and disease does not develop. Curative applications, Le. spraying established disease, are usually ineffective, except repeated applications of Dicarboximide fungicides. In most situations spraying at the first signs of disease development will give the best control of Fusarium Patch Disease. Thread (Laetisaria fuciformis (McAlp.) Burds.) During the summer months Red Thread, or Corticium Disease as it is sometimes known, may be common and disfiguring on fine and coarse (e.g. football pitches) turf. Red Thread has several characteristic symptoms that enable it to be distinguished from other turfgrass diseases. Generally, Red Thread appears as bleached areas 20-50 mm in diameter which may coalesce to form large irregular patches 0.35 m in diameter. Closer examination of affected areas reveals pink mycelium binding together leaf blades, cottony floes of mycelium and red stromata (commonly called needles or threads) as seen in Fig. 3. Although Red Thread may be found on most turfgrasses, the fine-leaved Red
fescues and perennial ryegrass (Lolium perenne) are most susceptible to the disease. Cultivar evaluation trials at STRI are monitored and assessed for severity of Red Thread and recommendations published annually (Anon. 1989). Selection of grass cultivars resistant to Red Thread is an effective disease management strategy. Red Thread is most common under low fertility conditions, particularly where the turf is deficient in nitrogen. as is often the case, for example, on golf course fairways where fertilizer is not normally applied. Football pitches which consist mainly of perennial rye grass are sometimes attacked by Red Thread in early summer when fertilizer applications made in spring have been utilised fully. Consequently, light, frequent fertilizer applications during the growing season will prevent severe attacks of Red Thread by ensuring adequate fertility. However. great care is needed as over-application can produce lush grass susceptible to Fusarium Patch Disease. If fungicides are thought necessary (usually careful cultivar choice and adequate fertilizer will prevent severe Red Thread attacks), then the Benzimidazoles mentioned above are effective. Take-All Patch Disease (Gaeumannomyces graminis (Sacc.) v. Arx & Olivier) Take-all Patch was relatively unknown in turfgrass until the 1950's when it was the practice to correct extremely acidic turf with applications of lime. As liming encourages Take-all (also the case in wheat), many severe outbreaks were recorded. Due to the very destructive nature of Take-all Patch, its persistence and the absence of an effective control measure, it is regarded as a serious problem in turf management. Symptoms of Take-all Patch usually appear in late summer or autumn. On fine turf, the disease often appears initially as saucer-shaped depressed areas consisting of dying bents. which are very susceptible. These small patches may then enlarge into a ring, measuring
18
Fig . 1: A typical scar produced by Fusarium Patch Disease . Not e th e orang elbrown colouralion . Fig . 2 : Stromata (needles or threads) produced by Red Thread . Fig . 3: Extensive damage by Take-all Patch Disease. Not e th e irregular rings of dying bents ex h ibiting an orangelbro wn colour ati on . Fig . 4: Fairy-rin g (Ma ra smius oreades) on a golf fairway.
up to 0 .3 m in diameter, of bleached or bronze bents , the centre of each ring being occupied b y plants resistant to the dis ease, such as fescues , a n nu a l meadow-grass and broad-lea ved weeds. Dying bentgrasses can be easily removed from th e turf, due to their rotted root systems. The roots and rhizomes of affected bents are blackened due to extensive production of runner hyphae, and perithecia may be observed under leaf sheaths at the base of the plant. There are several cultural conditions unique to golf turf that favour the development of Take-all Patch Disease. Firstly, in recent years, all-sand construction methods for golf, where greens are made by establishing a bentgrass monoculture on a pure sand rootzone, have become increasingly popular.
Greens constructed in this way have proved to be prone to th e di sea se , due presumably to th e ab se nce of antagonistic fungi and bacteria in the sand medium a n d rapid disease spread through a highly susceptible bentgrass sward . Secondly , constru ction materials are often sterilised and antagonists consequently reduced . Thirdly , greens are irrigated during dry weather by an automatic sprinkler system. In areas where the supply of water is 'hard', lime may be applied ev ery time watering takes place. Finally , most turf areas have a layer of thatch (partly decomposed grass remains) below th e turf surface which , in situations where Take-all is present, will act as a sub strate for a reservoir of fungal inoculum to surv ive unfavourable conditions during the winter
19 and cause re-infection the next spring. Once Take-all Patch has occurred adequate control is very difficult to achieve. Consequently. all efforts must be aimed at preventing disease outbreaks. Applications of lime should be avoided and sands used in construction or top dressing, and irrigation water should be analysed for its lime content prior to use. The phenomenon of Take-all decline, wetr documented for successive wheat crops, is also used to explain the progressive disappearance of the disease symptoms over several years in fine turf. As Take-all Patch recurs rarely on affected turf areas, natural decline offers a long term solution. Light applications of sulphate of iron (widely used on turf for moss control and improving turf colour) acidify the turf surface and thus partially inhibit the disease. Other Turfgrass Diseases Mature turf is attacked by a wide range of fungal diseases which vary in importance from those that generally only
cause minor damage, e.g. Powdery Mildew (Erysiphe graminis DC), to those that may cause more serious problems, such as Fairy Rings (Marasmius areades (Bolt.: Fr.) Fr.). The establishment of turfgrass seedlings may also be reduced by damping-off fungi attacking at both the pre- and post-emergence stage. A concise gu ide to the common fungal diseases of sports turf may be found in the STRI publication Turfgrass Diseases (Baldwin 1987). REFERENCES ANON (1989). Turfgrass Seed 1989. 12 pp. Sports Turf Research Institute, Bingley, England. BALDWIN. N A (El87). Turfgrass Diseases. 40 pp. Sports Turf Research Institute, Bingley, England. BOOTH. C (1971). The Genus Fusarium. 237 pp. Commonwealth Agricultural Bureaux, Kew, England. SYMES. B M C (1987). A Research Study and Review of Intensively Managed Amenity Turfgrass in the UK. Special report No.2. 40 pp. National Turfgrass Council, Bingley, England.
THE BERKELEY A WARD OF THE BRITISH MYCOLOGICAL SOCIETY T he Ber kel ey Aw ard , whi ch com me mora tes the co ntribu tio ns of th e Rev M J Berkeley (180 :1-1889) to myco logy, is mad e a n n ually a nd nomina ti ons are inv ited for 1!l!)0. The Candida te shou ld nor ma lly be und er :15 yrs on th e 1s t of Ja n ua ry of the Award year. Alt ho ug h the Ca ndi date need not b e a BMS Membe r, th e nom ination shall be proposed a nd secon ded by two Me m bers . A Cand ida te may be nom ina ted o n more tha n one occas io n bu t may o n ly rece ive a n A ward o nce . T he Award co nsists o f the Be rkel ey Cita tio n of the Society, toget he r wi th a s u m of £5 00 for use in furth er resea rch (in cluding boo ks a nd tra vel ), It wi ll be assessed on the bas is of ev ide nce of ou ts ta n d ing orig inal sc ie ntific co ntri bution wit h in any area of m ycol ogy , a n d may be s u p po rte d by p ub lish ed papers . T he co ntri butio n need not h av e been u nd e rtak en in th e Un ited Kingdo m. Nom inatio ns, w it h ev ide nce of th e work o n whi ch it is based , s ho u ld be sent by the nominators to the Ge ne ra l Sec retary . T he ev ide nce s ha ll co ns is t of a Curricu lum v ita e , an d a s u m ma ry of th e co n trib u tio ns mad e to m ycol ogy . In addi tion a co nc ise stateme nt of s u p p ort is al so re queste d. The closing date for n ominations is 31 March 1990. Th e A wa rd w ill be p rese n te d at th e Soci ety's Ann ua l Ge neral Meet in g in December. The recipie n t will be in v ited to d eliver a lect ure on h is/h er w ork at a s ubseq uen t scie n ti fic meeting , a nd this w ill be p ub lished in Myco logi co] Research .