contact - Čzuhome.czu.cz/storage/67623_forest protection_07b_student.pdfdeuteromycota, or fungi...
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RNDr. Dana Čížková, CSc.
Czech University of Agriculture Prague
Faculty of Forestry And Environment
Department of Forest Protection And Entomology
F O R E S T P A T H O L O G Y
Contact
• Dana Čížková
• Room number 227
• Tel. num. 224373840
• E-mail [email protected]
For a study:
http://www.forestpathology.org/index.html
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Diesases of the forest-tree species
Causal agents
Diesases induce organisms called a pathogens and vice versa,
a pathogen is an agent that causes disease. Pathogen can be only
living organism such as a bacterium or fungus (virus)
Which of fungi?
According to the way of nourishment we can divide them into three groups:
saprophytic
parasitic
symbiotic
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• Obligate saprophyte
• decays dead organic matter
• Facultative saprophyte An organism that is usually parasitic but may also lives as a saprophyte
• Obligate parasite: a parasite that can only feed on the living tissues of the host. Does not grow on artificial culture medium.
• Facultative parasite An organism that is usually saprophytic but which under certain conditions may become parasitic e.g. a fungus capable of operating at two trophic modes - decomposer and consumer.
What are fungi?
• Eukaryotic, spore-bearing, heterotrophic
organisms that produce extracellular
enzymes and absorb their nutrition.
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Spores - a minute propagative unit functioning as a seed, but
differing from it in that a spore does not contain a preformed
embryo
Fruiting body - any complex fungal structure that contains or
bears spores; a sporocarp
Ascomycota: (35 000)
•septate mycelium
•production of endospores (ascospores)
in an ascus
•often dominant asexual reproduction
Basidiomycota: (22 500)
•septate mycelium
•production of exospores
(basidiospores) on a basidium
•production of complex sporocarps
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Ascomycota (Sac fungi)
Sexual spore
(ascospores)are in
ascus and asci are usually
(but not always)
encased in ascocarps.
Asexual conidiospores
are common.
Ascus
• round to clavate to cylindrical
Bitunicate asci
www.bsu.edu/classes/ruch/msa/geiser.html
www.bsu.edu/classes/ruch/msa/geiser.html
www.mycolog.com/CHAP4a.htm
www.mycolog.com/CHAP4a.htm
www.botany.hawaii.edu/ faculty/wong/Bot201/Ascomycota/
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Hymenium
• fertile tissue of ascocarp
perithecium- flask-shaped sporocarp
-
www.kki.pl/zenit/grzyby_spyt/ga181.htm
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Stroma
• stroma: Mass of
fungus hyphae often
including host tissue
containing fruiting-
bodies with spores(pl.
stromata)
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stroma
stroma
Xylaria hypoxylon
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Hypoxylon fragiforme
apothecium - cup-shaped sporocarp
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hysterothecium
hysterothecium
Open hysterothecium with sacs (asci)
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Ascomycetes may have two distinct reproductive phases
• sexual: with asci and ascospores : Teleomorph
• asexual: with conidia: Anamorph
Ascomycetes classification is based on teleomorphs
Many ascomycetes are known only by their asexual stages.
Deuteromycota, or Fungi imperfecti
Fungi imperfecti (Deuteromycota)
teleomorph Venturia inaequalis anamorph Fusicladium dendriticum
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Deuteromycota
(Fungi Imperfecti)
• Asexual conidia only, or
mycelium only (mycelia
sterilia).
The Fungi Imperfecti lack a known sexual phase.
Conidium (conidia): Asexual spores
exposed on hyphal stocks.
Pycnidium (Pycnidia): Flask-shaped
organ containing asexual conidia.
Acervulus: Flat pustule containing asexual
conidia.
Basidiomycota
(Club Fungi)
Sexual spores are produced on the ends of club-like hyphae
(basidia). Asexual spores can (but don‘t have to) occur.
•
Basidia are usually located in specialized regions or tissues
(gills or pores)
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Agaricomycetes
mushrooms, shelf fungi
jelly fungi, coral
crusts, puffballs
Ustilaginomycetes
smuts
Urediniomycetes
rusts
3 Major Classes - of the Basidiomycota
Urediniomycetes (rust fungi)
• To complete the life cyclus very
often need 2 hosts.
Spores:
Aeciospores – in aecia
(pustules) mostly orange or
yellow
Uredospores – in uredia mostly brown
Teliospores – in telia mostly
nearly black
Basidiospores – on basidia
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Uredinales Chrysomyxa pirolata
aeciospores produced beneath the cone scales of spruce cones
Chrysomyxa pirolata
urediniospores
Orange-yellow urediniospores produced in uredinial pustules
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Phragmidium mucronatum
teliospores
Gymnosporangium sabinae (pear rust)
• Rust diseases are fungi with alternate hosts. The pear rust alternates between pear trees and Juniperus sabinae.
• On Pears first appear typical leafspot.
• From the leaf spots protrude aecia.These aecia
• bear the asexual aeciospores.
• Spores can be carried long distances in the wind,
• and thus infect nearby junipers
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Gymnosporangium sabinae
• On Junipers
• On junipers, the rust causes the development of swollen twigs. These swellings are teliospore masses also called telial galls. Telial galls swell up to a few centimetres wide. Teliospores produce the sexual spores on a basidium. These teliospore masses eventually ooze an orange gelatinous substance.
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Basidiomycetes Agaricomycetes
• Basidioma(ta) is the
formal term used to
designate the
basidiocarp or the
sporocarp (= fruiting
body) of
basidiomycetes
basidiomata are quite
variable in a shape (the
mushroom, puffball,
bracket, etc.)
Disease symptoms
• Necrosis
Tissue death resulting
in scorch, shot
hole or other symptom
of dead tissue:
color changes, necrotic
lesions, wilting, dieback
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Color changes
Necrotic lesions
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Damping off necrosis of colar
Necrosis of the bark
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Exudation
Exudation of
small droplets
honey-yellow or
milky-white ooze
„bleeding canker“
Wilting and drying up
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Dieback
canker
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canker
swelling
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Tumor disease
Witch brooms
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Twisting
Deformation
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Disease Control
• Protection
• Exclusion
• Eradication
• Therapy
Disease Control
Protection
• Surface • Precludes a pathogen from contacting a potential host
• Systemic • Introduce a chemical into the host to kill pathogens
attempting to colonize them at some later time
• Silvicultural • Maintain vigorous stands of trees which are better able
to biologically exclude infection from occurring
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Disease Control
- Exclusion -
• Vector Control • Prevent vectors from attacking potential hosts
• Quarantine • Prevent the spread of disease by not allowing movement
of infected host material into or out of specific areas
• Chemical/biological Treatment
• Fungicidal treatment of potential hosts or habitats, genetic manipulation of hosts or pathogens, culling of diseased stock prior to planting, and “escape” to disease
Disease Control
- Eradication
• Removal of diseased parts or individuals
• Pesticidal (chemical or biological)
treatment • Similar to exclusion – kills pest organism
• Habitat modification • Removal of bark to kill vectors or dessicate pests,
fumigation of soil or plant parts, dormant sprays of trees,
destruction of infected host material by fire or other
treatment, etc.
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Disease Control
- Therapy -
• Generally involves the use of systemic selective
chemicals - chemicals which are pest selective
and host neutral or beneficial
• Physical or Environmental Methods - removal of
an environmental element which is leading to
disease or damage
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Black rot-mummification of acorns Ciboria batschiana
Black rot-mummification of acorns
• Ciboria batschina is the fungus
(Ascomycota) causing black rot-mummification of acorns of Quercus spp. Ciboria spreads from affected fruits to unaffected acorns even at low temperatures (-1 °C), thus entire acorn crop may be destroyed during the first winter storage. Ascospores of the fungus can quickly infect acorn after they fall to the forest floor in the autumn, but also acorns on the trees can be infected. The only effective control of black rot is hot water treatment (thermotherapy - max. 42 °C for 10 hours or 46 °C for 4 hours) of acorns which kills the fungus, but not acorns. Also, if acorns are infected mainly after their fall to the forest floor the use of net suspended above the floor could decrease or prevent acorn infection.
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Damping off
• Damping-off is a disease of
germinating seeds and seedlings
caused primarily by fungi. The entire
seed may decay before germination or
the seedling may rot just below the soil
line. Healthy appearing plants selected
from flats with damping-off may
develop root rot or stem canker
several weeks later. With some
damping-off fungi, foliar blight may
also occur. Pythium, Fusarium,
Phytophthora, Rhizoctonia and
Alternaria are fungi that commonly
cause damping-off. There are many
other species of fungi that occasionally
cause this disease.
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Botrytis cinerea
grey mold
• Forestry harmful especially in nursery plants important for the spread is stable high air humidity attacks all species of trees, likes its ground after frost damage is capable of spreading even at temperatures around 0 ° C, humidity of about 95% at 85% conidia don‘t germination.
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Phytophthora cactorum
Crown rot Phytophthora cactorum
Phytophthora cactorum is a fungal disease that can infect
both the roots and the above ground parts of the deciduous
trees seedlings, especially of beech.
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Lophodermium needle-cast
• The name "needle cast" refers to a condition in coniferous trees where a sudden, severe loss of needles occurs. Lophodermium pinastri is the commonest fungus attacking the needles of pine. Symptoms: Brown spots, often with yellow margins, appear on the needles in the autumn. As the spots enlarge, the needles begin to yellow, then turn brown, and die by late spring or early summer. Later in the season on the fallen needles appear grayish-black, navicula -shaped fruiting bodies noticeable on all sides of the needles. These fruiting structures swell in wet weather, split down the center, and eject their ascospores.
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Powdery mildew on oak, (or oak mildew) is caused by the
ascomycete fungus Microsphaera alphitoides.
• During the initial stages of infection small chlorotic spots develop on the upper surface of young leaves and shoots. Grey-white patches of mycelium become visible on the leaves as the fungus spreads within its host's tissues. As the patches grow, they converge into larger patches on both the upper and lower leaf surface, and may eventually cover most of the leaf surface area. The conidia formed on the mycelium contribute to its powdery appearance. If and when cleistothecia are formed they can be seen with the naked eye.