Serious New Patch Diseases of Warm-Season Turf Grasses · Necrotic ring spot Ophiosphaerella korrae...
Transcript of Serious New Patch Diseases of Warm-Season Turf Grasses · Necrotic ring spot Ophiosphaerella korrae...
Serious New Patch Diseases of Warm-Season Turf Grasses
Dr Percy WongPlant Breeding Institute
University of Sydney
Overview
� Patch diseases of couch, buffalo and kikuyu
� ERI fungal diseases
� Five new serious diseases in the last 15 years� Fairway patch� Summer decline� Adelaide patch� Wongoonoo patch� Deniliquin patch
ERI Fungal Diseases
� ERI fungi = Ectotrophic Root-Infecting fungi
Diseased water-conducting tissues of roots
Classic ERI Fungal Diseases
Disease Pathogen Hosts
Take-all patch Gaeumannomyces graminis var. avenae Creeping bentgass , couch
Root decline of warm season turfgrasses
Gaeumannomyces graminis var. graminis Couch, warm season turfgrasses
Summer patch Magnaporthiopsis poae (Magnaporthe poae) Kentucky bluegrass, Poa annua
Necrotic ring spot Ophiosphaerella korrae (Leptosphaeriakorrae)
Kentucky bluegrass, Poa annua
Dead spot Ophiosphaerella agrostidis Creeping bentgrass
Spring dead patchOphiosphaerella narmariOphiosphaerella korrae Couch, buffalo, kikuyu
New ERI Fungal Diseases in Australia
Disease Pathogen Hosts
Fairway patch Phialocephala bamuru (BF1) Couch, kikuyu
Summer decline Wongia griffinii (Magnaporthe griffinii) Couch, hybrid couch, kikuyu
Adelaide patch Wongia garrettii (Magnaporthe garrettii) Couch, buffalo
Wongoonoo patch Gaeumannomyces wongoonoo Buffalo, couch
Deniliquin patch Budhanggurabania cynodonticola Couch
Patch disease on couch
Diseased roots
Steps in diagnosis
� Examine leaves, stems and roots under dissecting microscope
� Examine washed roots and stolons under dissecting microscope
� Examine root squash on slide under compound microscope for typical hyphae or spores
� Plate out infected roots on agar to isolate the pathogen or pathogens
Plating out infected roots and stems
Pathogen growing out of a diseased root
Isolation of fungi from diseased roots
Isolation of pathogen from diseased roots
Pure culture of the pathogen
How do we prove that a fungus is
the cause of the disease?
Koch’s Postulates
� The pathogen should always be associated with the disease
� The pathogen should be isolated from the diseased roots into pure culture
� If a healthy host is inoculated with the pure culture, the same disease symptoms should develop
� The same pathogen should be re-isolated from the diseased roots
Glasshouse test for pathogenicity
Disease symptom expression
Disease symptom expression
Re-isolation of the pathogen
Pure culture of the pathogen
Fairway Patch
Fairway patch on golf fairway
� Pathogen photo
Fairway patch on green surrounds
� photo
Bonnie Doon green surrounds and fairway
18th green surrounds at Royal Sydney
Fairway patch at The Australian Golf Club
Fairway patch at Avondale Golf Club
Fairway patch at New South Wales Golf Club
BF1 on two fairways at NSWGC
Fairway Patch at Kingston Heath Golf Club
Golf Clubs with Fairway PatchNSW�Bonnie Doon�New South Wales�Royal Sydney�The Australian (2015)�St Michael’s�Eastlake�Pymble�Avondale�Elanora�Ryde – Parramatta�Twin Creeks (near Penrith)�Pacific Dunes (near Newcastle)
QLD�The Grand�Pacific Harbour (2015)
WA�Gosnells (2015)�Mt Lawley (2015)�Collier Park (1016)
VIC�Kingston Heath (2015)
�SA ??
Affected turf species and cultivars
� Couch
� Wintergreen
� Windsor Green
� Santa Ana
� Legend
� Greenlees Park
� Common couch
� Kikuyu
Fairway patch in kikuyu
� photo
Fairway patch in kikuyu
� photo
Identity of the pathogen (BF1)
� BF1 has not produced any spores for easy identification
� Not a known turf pathogen like Rhizoctonia, Gaemannomyces orOphiosphaerella
� DNA work has shown that it is a new fungal species, Phialocephala bamuru
How does the pathogen spread?
How does the pathogen spread?
� Infected turf – divots, corings, sprigs, etc.
� Golf shoes, golf carts, other vehicles, wind
� Maintenance equipment – mowers, corers, earth-moving equipment
� Predictions
� It is only a matter of time before most golf clubs will be infected
� Turf farms could be infected if debris is brought back to the farms
Research on control of fairway patch
� Replicated field trials on infected golf fairways
� Strategic fungicide applications
� Biological control agents
� Organic and other amendments
� Cultural control
� Integrated control to manage disease
Field trial at Bonnie Doon Golf Club
Summer Decline
Summer Decline
� Patch disease of couch, hybrid couch, South African couch and kikuyu
� Found in Qld, NSW, VIC, SA and WA
� Caused by Wongia griffinii (Magnaporthe griffinii)
� Serious decline disease
� No satisfactory chemical control
Summer decline at Killara Golf Club, NSW
Summer Decline at Carbrook Golf Club, QLD
Diseased root systems
Diseased roots and stolons
Vascular discolouration of roots
Sexual stage of Wongia griffinii
Spores of Wongia griffinii
Adelaide Patch
Adelaide Patch
� First found in Adelaide (Colonel Light Gardens Bowling Club) on Greenlees Park couch
� Also occurs on buffalo grass in NSW
� Caused by Wongia garrettii (Magnaporthe garrettii)
� Devastating patch disease but is relatively uncommon
� No satisfactory chemical control
Adelaide Patch on bowling green
Sexual stage of Wongia garrettii
Spores of Wongia garrettii
Summer Patch
Summer Patch on the White House lawn
Summer Patch
� Caused by Magnaporthiopsis poae Landschoot & Jackson (1987)
� Disease of cool-season grasses
� Not found in Australia
� Preventative control possible with chemicals
Spores of Magnaporthiopsis poae
Wongoonoo Patch
Wongoonoo Patch in Buffalo
Take-all Patch in Tifdwarf Couch
Take-all PatchGaeumannomyces graminis var. avenae
Wongoonoo Patch
� Caused by a relative of the take-all fungus named Gaeumannomyces wongoonoo (Wong 2002)
� A patch disease similar to take-all patch in couch
� Occurs mainly on buffalo grass but has now been found in couch
� Chemicals that control take-all patch may be effective
Deniliquin Patch
Deniliquin Patch on Deniliquin Golf Club
Deniliquin Patch on a bowling green
Deniliquin Patch
� A devastating patch disease on couch
� Caused by a new genus and species of fungus� Budhanggurabania cynodonticola (Wong et al. 2015)
� It may be part of a disease complex
� Has not been controlled by chemicals
Budhanggurabania cynodonticola
Accurate diagnosis
� To manage turf diseases, an accurate diagnosis is essential
� Many disease symptoms look alike
� We often use American information on diseases but symptoms in the US may be different to those in Australia
� We also have diseases in Australia that do not occur in the US and vice versa
Disease Management
� For some of these intractable diseases, a long-term disease management program is required
� We may not be able to eradicate the pathogen
� Management would consist of using chemicals, biological control agents and cultural methods
� The long-term solution is to identify resistant cultivars
Management strategies
� Apply chemicals before couch comes out of dormancy
� Choose chemicals that are compatible with biological agents
� Apply biological control agents or organic amendments regularlye.g. composts or Trichoderma products
� Remove thatch to reduce the amount of the pathogen
� Fertilise judiciously to keep turf root systems growing actively
� If possible, mow at a height that does not stress the turf
Conclusions
� For ERI fungal diseases, diseased roots should be plated out onto agar to isolate the pathogens for an accurate diagnosis
� Accurate diagnosis allows chemicals to be used rationally or else money is wasted
� Build up local knowledge and not depend solely on information from the United States or the internet
� We should train more professional turf pathologists in Australia so that more research can be done locally