### condition | illness | disease | plant disease:

Canker
* Most cankers start from poorly healed branch stubs.
* allow the bacterium to overwinter.
* also cause such symptoms, and are sometimes confused with winter injury.
* appear as water soaked diseased areas, turn brown, shrivel and often girdle the stem
  - watersoaked diseased areas, turn brown, shrivel and often girdle the stem
  - elliptical along the length of the stem
* are a serious problem because they can girdle and kill limbs or the entire plant
  - source of inoculum which can initiate leaf, fruit, and wood infections
  - also common in nurseries and plantations where the plants are grown closely together
  - dark and depressed areas of dead bark and wood on main leaders and branches
  - diseases that attack the bark of trees
  - inconspicuous, with little or no bark deformation
  - most common on trees and shrubs under stress
  - places where the bark and wood have died
  - sunken areas in the bark that gradually get larger
  - typically sunken areas that are dark brown to purplish in color
  - ulcer
* become active in early spring as temperatures warm and buds begin to develop
  - elongated and sunken with ridges of callus tissue
* begin as small sunken areas and increase slowly in size.
* can cause foliage to turn yellow or brown and wilt
  - coalesce to M smaller shrubs within a year
* can develop and branches show dieback
  - on twigs, branches, or the main trunk
  - enlarge with age and become darker and rough-textured and retard plant growth
  - form on twigs, but they are rare
* can girdle and kill individual branches or twigs
  - stems
  - reach several feet in length
  - sometimes be one of the symptoms manifested by another disease
  - weaken the stem
* cause dieback of branches and kill trees if the trunk is infected.
* develop at or near the soil line, restricting water and food movement
  - in the fall after dormancy sets in
* develop on main trunk near ground level
  - twigs, branches, and trunk as the disease progresses
  - young tree trunks
  - slowly and can take four months to girdle a stem
  - when the pathogen kills the phloem and vascular cambium in a woody host
* enlarge more along the length than the width of the branch
  - yearly until the limb or trunk is completely girdled
* enlarge, girdle the stem before harvest, and kill the plants.
* eventually develop from branch or blossom infections.
* exhibit a scaly, papery outer bark that is often orange.
* form at the base of blighted twigs and spurs
  - on stems, branches and in branch axils causing dieback of shoots
  - where the disease enters a large branch or trunk
* frequently start at wounds or where a young shoot comes out of a cane.
* generally develop only on stressed or weakened trees
  - rapidly on winter-injured trees
* girdle and kill twigs and branches
  - the tree and can kill saplings while lopping branches off older trees
* gradually enlarge until infected limbs are girdled and then die.
* have a definite margin between the live and dead wood.
* infect, girdle, and kill branches.
* kill the cambium and girdle the stem.
* later become rough and crack open.
* often appear on plants weakened due to black spot
  - girdle the stems causing the foli- age beyond to wilt and die
  - show zoned ridges
* progress farther following severe winters than after mild ones.
* start as depressed areas on the bark which quickly girdle twigs, branches, or trunks.
* tend to form lower down first and then progress upwards throughout the canopy.
* then form on the stem causing wilting of the branch tip.
* usually have distinct margins between dead and living tissues.
* widen each year, and often coalesce, girdling the tree or branch.