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Fungus among us
By Linda Stephens-Urbaniak
Sometimes even the best plans just don't work out, and if you have planted a fruit tree in your yard, chances are that natural controls have not controlled several problems that arise. Bacterial and fungal diseases can attack trees, shrubs and herbaceous plants. While natural practices are best, there are times when the big guns are necessary. Be sure to wear protective gloves, goggles and even a mask or respirator when using dangerous chemicals, and change clothes and wash immediately upon finishing. It's also a good idea to wash work clothes separately from other clothes.
The best planning for fruit trees in our area comes with the choosing of disease resistant varieties, and planting where they get the best sun and drainage. Some diseases have no cure. For the best tree fruit varieties for Western Washington, call the King County extension service at 296-3900.
Brown rot or blossom blight kills flowers and also new growth and fruit on stone fruit trees such as peach, apricot, cherry and plum. It is a fungal disease, so control should be during the bloom cycle using a fungicide. The poisons of choice are wetable sulfur, Captan or Dacomyl 2787. The first application is at the opening bud stage. The flowers will look almost like popcorn. The second application is at full bloom; all the flowers are fully out. The third application is three to five days after the petals drop. Fungal diseases are hard to control so it is best to use more than one fungicide alternately. Caution, Captan should never be used on the winter flowering cherry, Prunus autumnalis.
Peaches are sometimes blighted with peach leaf curl. It can be controlled with three applications of lime sulfur. The first application should be in late December or early January on a day when the temperature is above 40 degrees. second application is about three weeks later and the third application about six weeks from the initial spraying, again paying attention that the temperature is above 40 degrees. ``Frost'' and ``Avalon pride'' are two peaches resistant to peach leaf curl.
Powdery mildew will attack many shrubs and perennials. It can be treated with 1 tablespoon of baking soda to a gallon of water and sprayed on the plant if the attack is early and not too extensive. Once it becomes extensive it can be treated with wetable sulfur, Dacomyl or, if container planted, with Bayleton, a systemic fungicide.
Apple scale, those brown scabs on the skin, can be treated with lime sulfur or wetable sulfur, Funginex or Captan. The first spray is at opening bud stage, the second when most of the flowers have fallen and the third about 10 days later. ``Liberty'' and ``freedom'' are resistant to most fruit tree diseases.
Dogwoods are especially susceptible to Anthracnose and it sometimes will hit apples, too. There is no cure. The tree must be removed, and no new tree that is susceptible planted there for at least three years, five years to be on the safe side. One dogwood, Cornus kousa, from the Far East is the least likely to succumb to diseases that make other dogwoods short lived.
Botrytis can be a problem with Peony and Hellebores. It can be controlled with a double application of wetable sulfur, once when the plant is emerging from the earth and another a week or so later. Be sure to wet the soil around the plant. Other controls are Greenlight, copper sulfate or Captan. Remove all old leaves in the fall and do not put them on the compost heap.
Other fatal diseases that can attack trees and shrubs are Bacterial chancre and viral infections. Removal is the only way to treat the problem. Never plant the same plant in the same area from which a diseased plant has been removed.
Natural methods are the best for gardens and health. Choosing the best trees and plants for the area will minimize the use of chemicals. When they are attacked, however, it is good to know how to handle the problem, as keeping gardens healthy helps to keep the entire ecosystem healthy.
You can reach Linda Stephens-Urbaniak at firstname.lastname@example.org