Phytophthora Diseases
-
Upload
planthealthresourcecenter -
Category
Education
-
view
638 -
download
0
Transcript of Phytophthora Diseases
Phytophthora Diseases
Gary W. MoormanPenn State
Plant Pathology & Environmental Microbiology
Late blight of tomato(Phytophthora infestans)
Phytophthora, Oomycetenot a true fungus
HyphaeChlamydosporesSporangiaAntheridia/oogoniaZoospores
Cell walls contain celluloseUsually has 2n chromosomes
Antheridium
Oogonium
APS Digital Image Collection
Phytophthora, sexual reproduction
A1 +
A2
mating types required
20-50 Zoospores per sporangium
Sporangium
APS Digital Image Collection
Phytophthora
plant pathogens
soil-borne??? …usually plant-borne
APS Digital Image Collection
Sporangium
Zoospore Release
Oospore germinatingby germ tubeOospore
Formation
Germinating oosporeby sporangium
Sporangium
Sporangium
ZoosporeReleaseSporangiophore
andsporangia
Zoospores
Oogonium &Antheridium
Life history and disease cycle of Phytophthora
A1 & A2mycelium
Asexualreproduction
Sexualreproduction
Wet conditions, 65F - 70F sporangia within 4 hours
Each sporangium > 20 to 50 zoospores released within 1 hour
Phytophthora activity
Phytophthora dispersal
Short distances
Splash
Wind
Long distances
Movement of
plants or soil
Phytophthora cactorum P. citrophthora P. citricola P. cryptogea P. drechsleri P. lateralis P. megasperma …many more P. parasitica P. syringae
P. nicotianaeP. ramorum
top diebacks, leaf spots, stem cankers
Phytophthora cinnamomi
infects 900 different species
Many Phytophthora species have a wide host range:
Phytophthora root rot
APS Digital Image Collection
Douglas-fir infected withPhytophthora spp.
APS imagecollection
Photo: Jennifer Parke, Oregon State University
Phytophthora root rotAPS Digital Image Collection
Severe root rot
Phytophthora cinnamomi on Ilex glabra ‘Shamrock’
Top dieback
APS Digital Image Collection
Top diebackV-shaped dead areas
APS Digital Image Collection
Symptoms on camellia
Photos: Oregon Dept. of Agriculture & Cheryl Blomquist, CDFA
Symptoms on camellia
Photo: Cheryl Blomquist, CDFA
P. ramorum symptoms on Kalmia
Photo: DEFRA
Sun scorch
Gray spot on sun scorched leaves
Similar symptoms – not Phytophthora
Photo: Rich Regan, Oregon State University
Photo: Peter Angwin, USDA-Forest Service
Not Phytophthora
Cercospora on Kalmia
Bleedingcankers
beech
beech
Photo by Joseph O'BrienBugwood.org image collection
Reddish-brown discolorationcambium area infected with
Phytophthora spp.
Phytophthora cactorum
Phytophthora citricola
Phytophthora plurivora
Phytophthora on European beech (Fagus sylvatica)
Weiland, Nelson and Hudler. 2010Plant Disease 94: 1009-1014
Taxus
Coastal live oak infected withPhytophthora ramorum
APS image collection
Phytophthora ramorum
Photos: Mike McWilliams, ODF & Bruce Moltzen, Missouri Dept. of Conservation
“bleeding”
Phytophthora ramorum
Sudden …usually slow
Oak …many other suscepts
Death …often not lethal
African violet infected with Phytophthora spp.
APS image collection
Penn State image collection
Hosta infected withPhytophthora spp.
APS imagecollection
Lavender infectedwith
Phytophthora spp.
APS imagecollection
Polemonium infected with
Phytophthora spp.
APS imagecollection
Catharanthus = annual vincainfected with
Phytophthora spp.
APS image collection
Phytophthora nicotianae on petunia
Phytophthoradetection
Phytophthora species in general:Antibody test (ELISA)Semi-selective media
Specific Phytophthora(P. ramorum)
Nested PCR DNA test
ELISA
Plating
PCR
Photo: Natalie Goldberg, New Mexico State University
Phytophthora detection
Baiting:
If you collect a sample Collect various stages
of symptoms.
Photo symptoms and environment.
Packaging a sample DRY paper towel Double bag and seal Crush proof box Sample submission form
outside of bags
Overnight express Monday-Thursday
Phytophthora ramorum
Photo: UC Davis & UC Berkeley
Phytophthora ramorum in culture
Chlamydospores
Sporangia releasing zoospores
QUESTIONS???