University:
Washington State University
Course:
BIOLOGY 409 | Plant Anatomy
Academic year:

2021
Views:

486

Pages:

37
Author:

strofamay59

Tree Disease Identification Stem and Branch 1: Cankers & Phytophthora diseases Invasive plant diseases Fungi Oomycetes • Phytophthora cinnamomi root • Chestnut blight (Cryphonectria disease parasitica) on American • Port Orford cedar root disease chestnut (P. lateralis) • White pine blister rust • Sudden oak death and (Cronartium ribicola) on Ramorum blight (P. ramorum) Western white pine on tanoak, oak, larch, many more. • Dutch elm disease (Ophiostoma ulmi) on American elm These are capable of eliminating certain host species from an ecosystem Chestnut blight caused by the fungus Cryphonectria parasitica Stem and branch diseases 1 • Cankers • Wetwood • Phytophthora • Management of canker diseases Cankers • Localized necrosis of the bark and cambium on stems, branches or twigs caused by fungi, bacteria, or abiotic agents. • Often centered around a wound or branch stub Cankers on Pacific madrone stem Types of Cankers • Annual • Perennial or Target • Diffuse Perennial or “target” canker caused by Nectria spp. Annual canker caused by Fusarium spp. Diffuse canker caused by Endothia parasitica (chestnut blight) Typical life cycle of canker fungi http://nysipm.cornell.edu/factsheets/treefruit/diseases/pc/pc_cycle.gif Nectria canker Tree hosts: Hardwood maple, apple, pear, plum, alder, oak Conifer- true firs, spruce, pine Shrubs: rhododendron, hydrangea, daphne Many others “Target” canker on alder Nectria canker • Asexual stage: Nectria cinnabarina, Neonectria galligena, Neo. ditissima • Sexual stage: Tubercularia Fruiting bodies (sporodochia) on spruce and maple Apple anthracnose and canker • Hosts: Apple (Malus spp.), mountain ash (Sorbus sitchensis), hawthorn (Crataegus spp.) • Pathogens: • Anthracnose: Cryptosporiopsis curvispora: (sexual: Neofabraea malicorticis) • Perennial canker: Cryptosporiopsis perennans (sexual: Neofabraea perennans) Apple anthracnose • Annual canker, but fungus fruits for 2-3 yr in dead tissue • Look for stringy detached bark • Bulls-eye rot on fruit Perennial canker of apple • Perennial “target” canker • Associated with wooly apple aphids • Same bulls-eye fruit rot as with anthracnose Botryosphaeria Canker Tree Hosts: madrone, maple, apple, cherry Shrub hosts: rhododendron, vaccinium, other Ericaceae Staining under bark on apple Canker and dieback on madrone Botryosphaeria canker Pathogens: Botryosphaeria arctostaphyli, B. berengeriana, B. philoprina, B. ribis, B. trames, B. vaccinii (Ascomycetes) Asexual stages in Fusicoccum, Neofusicoccum, Phyllosticta Spores of N. arbuti from madrone Dieback symptoms on cherry Eutypa canker • Hosts: Prunus, Alnus, Acer • Pathogens: E. armeniacae, E. flavovirens V-shaped canker caused by Eutypa lata in the xylem of a grapevine cordon. Eutypa vs Botryosphaeria Eutypa Both have • V-shaped cankers in xylem • Sooty appearance of cankered wood Botryosphaeria (Fusicoccum) • Branch dieback Pycnidia sliced open to reveal white interior Perithecial cavities, demonstrating a shiny inner surface characteristic of mature, dry perithecia. Eastern filbert blight • Hosts: hazelnuts (Corylus spp.) • Pathogen: Anisogramma anomala Eastern filbert blight is also a disease on the ornamental contorted filbert. Photo by Jay W. Pscheidt, 1996. Symptoms take 2 years to develop For more information http://pnwhandbooks.org/plantdisease/hazelnut-corylus-avellana-eastern-filbert-blight Eutypella canker Hosts: Alder, birch, maple Pathogen: Eutypella cerviculata, E. angulosa, E. alnifraga (Ascomycetes), E. parasitica on maples, not reported in WA Cytospora canker Hosts: many hardwoods including maples, birch, chestnut, ash, pear, elderberry, mountain ash, Conifers: douglas-fir and western red cedar An opportunist, symptoms severe on stressed trees Symptoms on apple Cytospora canker Pathogens: Cytospora chrysosperma, C. mollissima, C. thujae, C. kunzei (Ascomycetes) Sexual stages in Valsa, Leucostoma Yellow spore masses oozing from pycnidial stroma Conidia Cryptodiaporthe canker of poplar • Hosts: Lombardy poplar (most susceptible), other Populus spp. • Pathogen: Cryptodiaporthe populea (Ascomycetes) not reported in WA Conidia Fruiting bodies Tree failure from decay caused by Hypoxylon canker Canker rots Hosts: many hardwoods including maples, willow, poplar, alder, oak Pathogens: Hypoxylon spp. An opportunist, symptoms severe on stressed trees Bacterial canker Hosts: stone fruits (cherries, peaches, etc) Pathogen: Pseudomonas syringae The bacterial infection causes gummosis on branches and stems and can also cause fruit rot. Bacterial Wetwood Occupies the heartwood of some tree species • conifers: firs and hemlocks primarily • hardwoods: elms, poplars, birches, oaks • Bacteria feed on sap, lowering O2 and creating anaerobic environment, raising pH, and generating methane • These conditions help defend the tree from decay fungi. Bacterial wetwood and slime flux on elm tree at UW arboretum, Seattle, WA Managing bacterial wetwood • Avoid soil compaction and wounding • Drilling holes to relieve pressure does not help! • Sometimes insects are attracted to slime flux Phytophthora Sexual stage Sporangia containing swimming zoospores Chlamydospores Phytophthora is microscopic and species can be identified by spore stages and/or DNA sequencing Oospores (P. infestans) Heterothallic – requires two mating types for sexual recombination Homothallic – sexual recombination within the same individual (selfing) Phytophthora is not a fungus Eukaryote phylogenetic tree based on DNA sequence data Miklós Csűrös University of Montreal • Oomycetes were once considered to be fungi • Fungi and Oomycetes have similar growth forms – convergent evolution • Control agents for fungi may not work for Oomycetes and vice-versa Aquatic Phytophthora spp Common in waterways Weak pathogens • P. chlamydospora • P. lacustris • P. gonapodyides Any Phytophthora species can be detected using immunostrips, not all are aggressive pathogens. Phytophthora canker • Bleeding • No callus margin • Brown staining under bark • May come up from roots • Best ID’d from host range, symptoms P. cambivora – many hosts P. cinnamomi – Eucalyptus and others P. alni ssp. alni – alder P. lateralis – Port Orford cedar P. ramorum – Sudden Oak Death P. cambivora Host range: Conifers and hardwoods Geographic range: Europe and North America Origin: unknown Important diseases: Ink disease of hardwoods, root rot on Abies spp. • Root disease & basal canker • Heterothallic P. cambivora causing dieback on European beech (Fagus sylvatica) in Germany P. cinnamomi Host range: Hardwoods and conifers – more than 1,000 species Geographic range: worldwide Origin: Indonesia Important diseases: Chestnut ink disease, ink disease of oaks, Jarrah dieback of eucalyptus, Avocado root rot, littleleaf disease of pine • Root disease & basal canker • More aggressive in warm soils • Heterothallic P. cinnamomi on Pacific madrone, CA P. alni ssp. alni Host range: Alnus spp. Geographic range: UK, 18 European countries Origin: UK Important diseases: Alder root rot Oospore of P. alni • Root disease & basal canker • Homothallic • Hybrid of P. alni ssp. uniformis and P. alni ssp. multiformis, which are hybrids of P. cambivora and P. Mature common alder (A. glutinosa) with collar rot by P. alni (note tarry spots at the outer bark) growing in a fragariae forest stand in Germany; introduction of the pathogen via alder plantation in the neighbourhood established with infested planting stock. Phytophthora lateralis Host range: Port-Orford cedar (Chamaecyparus lawsoniana), C. obtusa, Pacific yew (Taxus brevifolia), Thuja occidentalis Geographic range: UK, France, Netherlands, Pacific Northwest, Taiwan Origin: Possibly Taiwan Important diseases: Port Orford cedar root disease • Root disease & basal canker • Heterothallic Aerial infections in France and coastal Oregon. Breeding program for resistant POC in Oregon Mortality from P. ramorum infection at China Camp State Park, CA. P. ramorum Host range: more than 100 hosts Geographic range: CA, OR, WA, UK, Europe Origin: Unknown Important diseases: Sudden oak death, Ramorum blight • • • • Canker and foliar blight Aerial infections Heterothallic Regulated Ramorum blight on Camellia sinensis ‘Sochi’ in nursery P. ramorum distribution in forests Western US – oak, tanoak UK - larch SOD symptoms on trees P. cambivora on Beech • Bleeding cankers • Cankers can girdle the tree and kill it • Host species in Fagaceae: oaks, beech, tanoak • Other Phytophthora spp can cause the same symptoms P. ramorum on Oak Managing canker diseases • Moisture control • Prune in dry weather • Sanitation – pruning tools, weed control, remove dead material • Prevent or reduce wounding, including sunscald and winter injury to trunks • Improve tree vigor • Preventative chemical treatment on high value trees

Tree Disease Identification Stem and Branch 1 Cankers and Phytophthora diseases

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