Download - Sudden Oak Death: biology and management
Sudden Oak Death: biology and management
PathogenPathogen
HostsHosts
EnvironmentEnvironment InteractionsInteractions
Man
Phytophthora ramorum: Sudden Oak Death
Phytophthora kernoviae: blights & cankers, UK
Phytophthora alni: Alder decline, Europe
Phytophthora pinifolia: Daño Foliar del Pino, Chile(Pine needle blight)
Phytophthora quercina: Oak decline, Europe
Historic:
Phytophthora cinnamomi: Jarrah decline, Australia
Phytophthora lateralis: Pt. Orf. Cedar Root Disease, OR/CA
Phytophthora forest diseases:
Phytophthora diseases:
Well known in ag systems on numerous crops
Destructive in poorly drained soils or cool wet climates.
Disperse via motile zoospores
Survive as thick-walled chlamydospores or oospores
Mainly root diseases
Some cause aerial diseases of foliage, shoots or trunks
Sudden Oak Death
Mortality since 1990s
Phytophthora ramorum sp. nov. identified 2001
Consistent expansion of range (depends on season)
Wide host range reminiscent of P. cinnamomi
Sudden Oak Death
Lethal trunk infections on some native Quercus spp. & Tanoak
California Bay Laurel principal cause of dissemination in forests
Hosts like Rhododendron, Camellia, & Viburnum significant for spread through ornamental stock
Sudden Oak Death
Spread aerially by wind & rain during mildwet season
Introduced into new areas on infested ornamental stock
May be moved by people in infested soil or plant debris.
Starting in 1994 in Santa Cruz County(but probably arrived late 1980s)
Phytophthora ramorum
Sporangia
Chlamydospores
SOD pathogen called SOD pathogen called Phytophthora ramorum Phytophthora ramorum arrivedarrivedto California in 80s on infected ornamental plantsto California in 80s on infected ornamental plants
Positive isolationP. ramorum
Known distribution of Phytophthora ramorum in August 2000
Known distribution of Phytophthora ramorum in August 2008
Positive isolationP. ramorum
(OAKMAPPER.ORG)
P. ramorumP. ramorum introduced at least 8 times in CA introduced at least 8 times in CA (Mascheretti et al. 2009). Multiple introductions and not (Mascheretti et al. 2009). Multiple introductions and not
ability to move far explain distribution of diseaseability to move far explain distribution of disease
Because pathogen is exotic, native flora has limited resistance to its attack and regular tree health maintenance simply will not suffice
Cluster 1 of strains is the
original introduced,
butothers are
more widespread
Distribution of SOD in California wildlands
• Distribution is result of discrete introductions followed by natural spread but only in favorable habitats (redwood-tanoak and mixed evergreen)
• As a result, distribution is extremely patchy in 14 contiguous coastal counties from Northern Humboldt to Southern Monterey
• Presence is extremely marginal in San Francisco, Solano, and Lake counties
Bay/Oak association
Bleeding cankerBleeding canker
Canker margin in phloemCanker margin in phloem
Bay Coast Live Oak (no sporulation)
SporangiaSoil
Yearly
Wave years
OaksCoast live oak
Quercus agrifolia
Black oakQ. kellogii
Shreve’s oakQ. parvula var. shrevei
Canyon Live oakQ. chrysolepis
TanoakNotholithocarpus densiflorus
Tanoak leaves alsovery infectious:-tanoaks behave bothas oaks and bay
Hypoxylon Hypoxylon (Anulohypoxylon) (Anulohypoxylon) fruitbodies on the main fruitbodies on the main stem are a sign that a tree stem are a sign that a tree is functionally deadis functionally dead
Only health compromised trees attract bark and Only health compromised trees attract bark and ambrosia beetles: frass (sawdust) on the trunk is ambrosia beetles: frass (sawdust) on the trunk is
a sign of insect colonizationa sign of insect colonization
Tanoak vs. Oak mortality
• Tanoak – Big Sur– 70%
• Marin – predicted– 15 years for 90%
• Oak- Big Sur– 40%
• Marin – predicted– 35 years for 90%
Confirmed Susceptible Species
Andrew's clintonia bead lilyArdisiaBearberryBigleaf mapleBlueblossomCalifornia bay laurelCalifornia black oakCalifornia buckeye California coffeeberry California hazelnut California honeysuckleCalifornia maidenhair fernCalifornia nutmegCalifornia wood fernCamellia speciesCamphor treeCanyon live oakCascaraChinese witchhazel Chinese guger treeCoast live oakCoast redwoodDogwood speciesDouglas firEastern Joy Lotus TreeEuropean ashEuropean beech
European turkey oak European yewEvergreen huckleberryEvergreen mapleFalse Solomon’s sealFormosa firethornFetterbushGoat willowGrand firGriseliniaHollyHolly oliveHolm oakHorse chestnutHybrid witchhazelJapanese evergreen oakLaurustinusLeucothoe speciesLilacLoropetalum speciesMadroneMagnolia varitiesManzanitaMicheliaMountain laurel
Myrtle-leafed DistyliumNorthern red oakOleanderOregon ashOregon grapeOsmanthusPacific yewPersian ironwoodPieris varietiesPlanetree maplePoison oakPrunus speciesRed firRed lotus treeRed tip photiniaRedwood ivyRhododendron speciesRoble beech Rosa species & hybridsRosa species & hybridsRugosa roseSalalSalmonberryScotch heatherScribbly gumSessile oak
Sheep laurelShreve’s oakSouthern red oakSpicebushSpike witch hazelSpreading euonymusStar magnolia Strawberry treeStriped bark mapleSweet bay laurelSweet chestnutSweet CicelySweet oliveTanoakToyonViburnum varietiesVictorian boxVine mapleWestern maidenhair
fern Western starflowerWhite firWinter's barkWitch hazelWood roseYew
Confirmed Susceptible Species
Andrew's clintonia bead lilyArdisiaBearberryBigleaf mapleBlueblossomCalifornia bay laurelCalifornia black oakCalifornia buckeye California coffeeberry California hazelnut California honeysuckleCalifornia maidenhair fernCalifornia nutmegCalifornia wood fernCamellia speciesCamphor treeCanyon live oakCascaraChinese witchhazel Chinese guger treeCoast live oakCoast redwoodDogwood speciesDouglas firEastern Joy Lotus TreeEuropean ashEuropean beech
European turkey oak European yewEvergreen huckleberryEvergreen mapleFalse Solomon’s sealFormosa firethornFetterbushGoat willowGrand firGriseliniaHollyHolly oliveHolm oakHorse chestnutHybrid witchhazelJapanese evergreen oakLaurustinusLeucothoe speciesLilacLoropetalum speciesMadroneMagnolia varitiesManzanitaMicheliaMountain laurel
Myrtle-leafed DistyliumNorthern red oakOleanderOregon ashOregon grapeOsmanthusPacific yewPersian ironwoodPieris varietiesPlanetree maplePoison oakPrunus speciesRed firRed lotus treeRed tip photiniaRedwood ivyRhododendron speciesRoble beech Rosa species & hybridsRosa species & hybridsRugosa roseSalalSalmonberryScotch heatherScribbly gumSessile oak
Sheep laurelShreve’s oakSouthern red oakSpicebushSpike witch hazelSpreading euonymusStar magnolia Strawberry treeStriped bark mapleSweet bay laurelSweet chestnutSweet CicelySweet oliveTanoakToyonViburnum varietiesVictorian boxVine mapleWestern maidenhair
fern Western starflowerWhite firWinter's barkWitch hazelWood roseYew
Primary cause of death is girdling of phloem, vessel blocking, while secondary organisms accelerate the
process
Girdling occurs much faster than visible symptoms on crown. Girdled trees can survive apparently “green” 4 years + after being girdled
Girdled trees can fail even if “green” because of activity of secondary organisms
While insecticides may temporarily prolong the life of treated trees, beetle attacks are a good indicator of “hazard” trees
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By inoculating with By inoculating with zoospores and without zoospores and without wounding, the ideal wounding, the ideal conditions for infection conditions for infection were figured out: these were figured out: these conditions are present in conditions are present in California especially when California especially when there are rainy late there are rainy late Springs: these conditions Springs: these conditions do not happen every year do not happen every year
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SOD spore catches in water: mid-April to mid-June is consistent
Synchrony pathogen-host:Host susceptibility
Susceptibility of oaksSusceptibility of oaks(lesion size in lab)(lesion size in lab)
Susceptibility of bay Susceptibility of bay laurelslaurels(lesion size in nature)(lesion size in nature)
PathogenPathogen
When multiple rain events occur sporangia are When multiple rain events occur sporangia are produced on leaves of infectious hosts such as produced on leaves of infectious hosts such as bay laurel and tanoak and can be airborne bay laurel and tanoak and can be airborne
mostly up to 100 m but when mostly up to 100 m but when winds are strong up to 2 mileswinds are strong up to 2 miles
New infections occur almost exclusively during the rainy season in or near sites previously infested
Limit tree-care and forestry work during wet season
If necessary to work in wet season, schedule to work in uninfested sites before working in infested sites
P. ramorum has a short spread range, knowing its fine scale distribution is essential