Most of us are familiar with the large tree, the American sycamore. It's the one with the large leaves, flaking white bark, and the small balls for seed heads that favors growing along stream banks or sites with plenty of moisture.
You may also have observed that it has trouble getting leaves in the early spring. Close inspection would have shown disease killing the first round of leaves. Fortunately for this plant, a second flush of leaves forms and by mid summer you see few traces of this spring problem.
The disease is Anthracnose. It thrives in cool, moist conditions. Naturally, we can suspect that 2004 was an exceptionally bad year. The real problem is that Anthracnose or some strain of it attacks many plants in our gardens or landscapes.
Tomatoes and vine crops are targets in the vegetable gardens. The plant breeders have done an excellent job of creating plants with a high level of resistance. Some of the heirlooms can be troubled, but these problems can be mitigated with careful sanitation or chemical fungicide.
A target in our landscapes is the popular common dogwood. With the dogwood, Anthracnose can be a fatal problem. Drive through the southern Appalachian and Smoky Mountains in the spring and you will see the demise of the native dogwood.
Normally the dogwood is an under-story tree, which is usually a slow drying site. The disease flourishes on wet leaves, and will attack new growth, killing branch tips and eventually weakening and destroying the tree. If you see twig death in one of your dogwoods, it should be cut out, cutting about a foot below the visible infection.
The good news is that we are just on the northern edge of the area with the greatest damage. In fact, I have a pair of pink ones in my yard for the last dozen years who never have shown anything beyond leaf damage. There are reasons, and I will get into that in a few sentences.
As with other plants, the breeders have made crosses that offer resistance. Using the Latin, the native Cornus florida is the biggest problem. If you find cultivars with fancier names, your plant will have some level of resistance. The large flowered, late blooming Kousa dogwood is resistant.
Plant talkers frequently use the word resistant in their descriptions. Don't be mislead. Resistance means added defenses but never total disease victory. Remember that.
Back to the dogwood, the key to success is cultural practices. As I said, the dogwood is an understory tree, but the fact is that it can grow in full sun where its leaves will dry more quickly. Avoid wetting the leaves with irrigation. Provide good air circulation.
I practice the above with my pink Cornus florida and have yet to face the need to remove dying branches.
Diseases, even with the same name, have varied looks and effects on different plants, but diseases can be managed. Practice sanitation. Check for resistance. Avoid excessive irrigation. Do not put problem plants in problem sites. Occasionally you may need some chemical aids.