Tree Diseases

Tree Diseases

Trees are more difficult to diagnose in that they react slowly, have a multitude of issues creating the final problem and are often affected by environmental changes such as excavation or compaction.

When trying to determine the health issue use a check list such as this:

1. What type of tree is it?

Each species has its own characteristic insect or disease

problems.

2. What is the approximate age or tree size?

Often, certain problems are associated with a particular

stage of a tree’s life.. Newly transplanted

trees, for instance, often show stress symptoms.

3. What kind of care is the tree receiving?

Has the tree been watered or fertilized? How often and

how much?

4. Is there evidence of injury to other surrounding

plants?

The presence of injury symptoms on different species

suggests a general environmental or chemical factor is

responsible for damage or decline.

5. Have there been untimely frosts or freezes?

Late-spring frosts or sudden exposure to freezing

temperatures can result in wilting, blackening, or death

of newly emerging growth.

6. When did the symptoms first appear?

How quickly did the problem develop? Some insect and disease

problems show up at certain times of the year, or during

certain weather-related events.

7. What portion of the tree is showing the

problem?

Is the problem evident over the entire tree, just the upper

branches, one large branch, the main trunk, etc.?

8. What is the soil type (clay, sandy, etc.)?

Certain tree species perform best on particular soils.

Applicators often see the same problem on specific species over and over during a time period. You can contact the local extension office for common problems being reported that week.

Here are a few common issues to help you start the identification process and web sites that can give detailed information:

Anthracnose on Sycamores is caused by a fungus especially during wet, warm spring weather.
A fall systemic treatment is best or spraying early in the Spring according to label.http://www.ksre.ksu.edu/path-ext/factSheets/Trees/Anthracnose%20Diseases%20of%20Shade%20Trees.asp
http://www.uri.edu/ce/factsheets/sheets/anthractrees.html

Fire Blight (example on this Pear) is a bacterial disease and is another Spring disease. Control methods are sometimes difficult to schedule for applicators and may include pruning and other services.
http://www.nysipm.cornell.edu/factsheets/treefruit/diseases/fb/fb.asp
http://www.ces.purdue.edu/extmedia/BP/BP-30.html

Cedar Rust is often identified by bright yellow/orange lesions that develop into fruiting bodies that are very distinctive. It can be managed with fungicides, however registered fungicides will vary by the type of plant(s) to be treated and their use or site so always read the label.
http://plantclinic.cornell.edu/FactSheets/cedar-applerust/cedar-applerust.htm
http://urbanext.illinois.edu/focus/cedarrustdiseases.cfm

Needle Blight on Pine can be controlled by fungicides. Keep in mind that some needle blight diseases could need as many as three or four spray applications 8 to 10 weeks apart beginning in April and ending in October. Read the label and know what fungicide you are going to recommend to the customer and what the application will be before bidding the project.
http://www.na.fs.fed.us/spfo/pubs/fidls/br_spot_pines/brown-spot.htm
http://www.na.fs.fed.us/spfo/pubs/fidls/dothistroma/doth.htm

Oak Leaf Blister caused a fungus members of the red oak group are particularly susceptible to infection. Disease development is favored by cool, wet springs. A single application in early spring just before the buds begin to swell can effectively manage this disease. Fungicides will not be effective if applied after bud break.

Sooty Molds are in that series of factors that a tree may be going through that is creating the end problem. Aphids secrete honey due and sooty molds feed on the honey dew; if you as an applicator have controlled the aphids and scale this can be prevented.
http://www.na.fs.fed.us/spfo/pubs/howtos/ht_sooty/ht_sooty.htm
http://www.ag.ndsu.edu/pubs/plantsci/hortcrop/pp697-1.htm

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