Tree pathology terms

tree/forest pathology

the study and management of diseases and pests that impact trees and forests

disease

a malfunction of a metabolic process/disturbance of normal structure and results in a continued irritation

leaf spot pathogens

round/free-form legions on leaves resulting from individual infections

ex. tar spot of maple

anthracnose

infection characterized by dark discoloration and collapse of leaf blade tissue

ex. sycamore and dogwood anthracnose

needle blight

group of pathogens that infect conifer needles and girdles them

ex. dothistroma needle blight of pine

rust diseases

caused by fungi with complex life cycles that require at least two different, often unrelated hosts and produces orange-red (rust) spots

ex. white pine blister rust

wilt and stain fungi

colonize xylem vessels, inhibit water conduction, causing leaf wilt and eventually killing the tree

ex. dutch elm disease, oak wilt disease

canker diseases

caused by fungi that infect twigs and branches, and causes cankers on the stem

ex. hypoxylon canker of aspen, chestnut blights

stem decay

fungal decay of inner wood, usually heartwood

conks

fruiting bodies of shelf fungi

root diseases

attack roots/lower part of the stem

ex. armillaria root disease

facultative saprophyte

can live off living roots and continues to do so after it kills its

defoliators

insects that eat leaves

includes: caterpillars, beetles, sawflies, and walking sticks

bark beetles

bore into trunk and feed and reproduce in vascular cambiems and adjacent xylem and phloem

ex. mountain pine beetle, emerald ash borer

galleries

tunnels under bark made by bark beetles

wood borers

bore into trunk and tunnel deep into sapwood

ex. asian long-horned beetle (a generalist, attacks hardwoods)

sucking insects

pierce foliage, twigs, or roots and suck sap as food

includes: aphids, scales, and spittlebugs

ex. hemlock woolly adelgid

shoot/bud insects

feed on growing tip of a plant and cause stented growth and copious branching

ex. white pine weevil

root insects

feed on roots (or stems) at the base of a tree

ex. white grub and cicadas

vector

an organism that transmits a pathogen from one host to another

complexes

more than one agent causes disease and each contributes directly and significantly

ex. dutch elm disease

decline diseases

interactions of abiotic and biotic agents, leading to a gradual reduction of tree health

ex. sugar maple decline (think of the diagram)