I live in Kitsap and my 50-year old maple is dying — what should I do?
Also, my Dogwood trees seem to be infected with anthracnose. Can you give me some information about this disease?
To get some information about your maple, you can consult with a Master Gardener at a WSU Kitsap County Extension Diagnostic Clinic.
Regarding dogwood anthracnose (Discula destructiva), it is a shame that so many of these beautiful trees are infected. You may be somewhat reassured to know that although the disease often causes tree death in the northeastern U.S., here in the Pacific Northwest, many trees survive. Douglas Justice, Curator of Collections at University of British Columbia Botanical Garden, discusses this on the UBC discussion forum.
Excerpt:
“Weather is probably the deciding factor in infection. A cool, wet period seems to be most conducive to infection, and such factors probably have to coincide with a specific time of tissue susceptibility. In other words, the conditions have to be “just right” for the disease to take off and become established. However, it is well documented that stress predisposes plants to disease susceptibility. Stressors for Cornus nuttallii (Pacific dogwood) would include compacted soil, poor drainage, full exposure with overly dry soil (C. nuttallii is adapted to a summer drought regime, but let’s be reasonable!) and wet soil in summer (e.g., irrigated soil — see previous comment).
Nearly all the local anthracnose-affected dogwoods recovered, including the wild natives and the even some of the more severely affected C. florida (eastern dogwood). Anthracnose has visited us subsequently, but mostly only on C. florida and urban C. nuttallii. This suggests that the there isn’t much anyone can do to prevent the disease from occurring and that as along as trees aren’t overly stressed, they will eventually recover. ”
A U.S. Forest Service article entitled How to Identify and Control Dogwood Anthracnose includes images which may help you to determine if your tree has anthracnose.
Master Garden Products.com provides a short article about dogwood anthracnose that contains a What to Do list.
University of Maryland College Home and Garden Information Center’s Integrated Pest Management Series HP #12 offers information about dogwood diseases and pests, including anthracnose.
Oregon State University Extension’s Online Guide to Plant Disease Control describes cultural controls for anthracnose. There is also an extensive list of chemical controls, which you may choose to ignore after reading Douglas Justice’s comments from the UBC discussion forum mentioned earlier:
“The application of fungicides is probably a waste of money and also likely counter-productive, particularly with a systemic such a benomyl, which will kill most of the good fungi, but probably not the target pathogen. Common fungal pathogens frequently develop resistance to this fungicide.”