Root Disease Management Guidebook Table of Contents]


Basal resinosis (pitching): large exudations of pitch at the base of the stem at, or below, the root collar. This symptom is often characteristic of Armillaria root disease.

Ectotrophic mycelia: where fungal hyphae form a closely woven envelope covering the root and penetrating to a limited extent between the cells.

Hazard: the degree to which the characteristics of a tree or stand make it vulnerable to damage. It is equivalent to susceptibility.

Incidence: the proportion of damaged or affected trees within a stand or area.

Inoculum: refers to the amount of underground woody material infected with, or potentially able to be infected with, a root disease pathogen, and available for infecting regeneration or remaining residual root systems (e.g., infected stumps and root systems left after harvest without stumping or pushover harvesting).

Living stump: created when live trees are cut and their stumps remain in the ground. The stump and root system may remain alive for several years or more if root grafting to neighbouring live trees occurs.

Pathogen: any agent, whether a living organism or abiotic agent, that induces disease.

Risk: the probability and expected severity of damage as determined by a function composed of host susceptibility; suitable environmental conditions (both combined equate to hazard); plus pathogen proximity, abundance, and virulence.

Saprophyte: an organism that commonly feeds on dead organic material, usually by decomposing and absorbing it, assisting in its decay, but which may in exceptional circumstances attack living hosts (e.g., those weakened by primary pathogens or stress).

Signs: visible portion of a pathogen, or its products, seen on or in the host plant.

Stand dynamics: the study of changes in forest stand structure over time, including stand behaviour during and after disturbance.

Symptoms: visible reaction of the host plant to infection, disease, or other pest attack.

Walkthrough: initial reconnaissance of an area used to make a preliminary assessment of site conditions and suitability for further surveys or activities.

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