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Blue and Norway spruces are susceptible to a branch killing disease caused by the fungus Cytospora kunzei.

Bacteria are microscopic, single-celled organisms that have a cell wall.

Informational table showing disease name, symptoms, pathogen/cause, and management of Elm diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Maple diseases.

Many mature trees, including elms, oak, tulip poplar, and maple, exhibit large light or dark vertical streaks on their trunks.

While most nematodes are soil-dwelling, the foliar nematode Aphelenchoides lives only briefly in soil.

Informational table showing disease name, symptoms, pathogen/cause, and management of Willow diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Euonymus diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Catalpa diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Pachysandra diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Poplar diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Oak diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Privet diseases.

The fungus Nectria invades wood damaged by freezing, hail, animals and insects.

Fire blight is a disease caused by the bacterium Erwinia amylovora.

Informational table showing disease name, symptoms, pathogen/cause, and management of Taxus diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Leucothoe diseases.

Common tree fruit questions from home gardeners are "Why do my trees fail to bear fruit?" or "Why do they only have fruit every other year?"

In Pennsylvania, anyone making pesticide applications to land that they do not own or lease is required to have at least one Certified Pesticide Applicator.

Two closely related viruses have been widespread and devastating in the greenhouse industry.

Austrian, Scots, ponderosa, mugo, red, and other 2- and 3-needled pines are susceptible to the killing of shoot tips and branches by the fungus Diplodia pinea (formerly Sphaeropsis sapinea).

Informational table showing disease name, symptoms, pathogen/cause, and management of Hosta diseases.

Informational table showing disease name, symptoms, pathogen/cause, and management of Amelanchier diseases. (Shadbush, Serviceberry)

Needlecast diseases of evergreens are caused by several fungi.

Fungus-like organisms belonging to the genus Phytophthora are soil- or plant-borne and all are plant pathogens.