Root disease Flashcards
(24 cards)
Which layer is thicker, mor or mull?
Mor, because it is slower to decompose
Where would you expect to find mors? mulls?
Mors - conifer overstory
Mull - deciduous overstory
Why do needles break down slower than leaves?
Needles typically have a longer “shelf life” and are infused with defenses which slow the rate of decomposition.
What are the overall attributes of mineral soil?
- Cooler
- Less OM
- Less microbial activity
What are some variables that effect mineral soil?
Texture
- fine vs coarse
- fine = more water and low temperature
- coarse = less water
What is Mycostasis
Inhibition of fungal growth.
What are the 3 causes of mycostasis?
Antagonism - fungal warfare between species inhibits both
Competition - for water nutrients and energy
Harsh environment - Temperature and moisture conditions can arrest fungal development
Where is mycostatis the most prominent?
in the LFH, because that is where most fungus are and the least resilient layer to environmental changes.
What is the tea break fungus?
Heat from repeated fires sterilizes soil, except for a fungus known as the tea break fungus which can establish the sterilized soils and survive hot conditions. Kills surrounding trees.
What are the 4 groups of root Fungi?
SOIL INHABITING (asco) -not host specific - lie dormant as spores awaiting young roots - primarily a nursery problem MYCORRHIZAE (zygo, asco, basidio) - symbiotic WILTS (asco) -typically very host specific -live in sapwood -transpiration issues kill tree -black stain + dutch elm ROOT INHABITING DECAYS -host specific -similar to heartrot/ wood decays -cannot travel freely in soil (mycostasis) -Facultative saprophyte (Mainly a parasite)
What is a facultative saprophyte?
Organism is primarily a parasite but can survive on dead wood
How do root rots spread?
Root grafting
List the root structure
Bark -outer bark -periderm -inner bark Cambium Wood -sapwood -heartwood
How to Roots decays initially infect hosts?
- Spores
- Vegetative (root contact)
- Moves quickly down outer bark and more slowly inside due to defenses.
Why do rood inhabitors stay below LFH?
Mycostasis in LFH arrests upward rot development.
What are some name examples of root inhabiotors
Annosus, Tomentosus, Phelinus (laminated root rot).
What are the typical symptoms of root disease?
- Decreased growth (shortened leaders/stalled growth)
- Thinning/Chlorotic crown (Yellowing)
- Stress cone crop (High number of small cones typically on young tree)
- Windthrow/Break ( Throw Typical with phellinus. Natural broken hollow stump. Break typical with armillaria)
- Centres ( creates pockets/patches in stand due to mortality )
- Tree sweep on flat ground (compromised root structure)
What does the term chimney refer to?
Hollow stump left behind after windbreak associated with armillaria.
What is the code for Armillaria? What about Phellinus?
DRA
Disease Rot Armillaria
DRL
Disease rot laminated
What is a term for fungi that can survive and travel in soil?
Rhizomorph
What is DRL? Which species are at risk?
Phellinus weirii
P. sulphurescens
(Laminated root rot)
-Infects Fd (sulphurescens) and Cw (weirii).
What is type of rot is the cedar form of DRL?
A butt rot
What sections are the soil expressed in?
OM Litter Fermentation Humus - colloidal organic matter A horizon B horizon C horizon
Define quiescent
In a state or period of inactivity/dormancy
