Dutch Elm Disease
For generations, the American elm (Ulmus americana), with its graceful wineglass form, was its graceful winglass form, was a favorite large shade tree throughout much of the United States. But,because of the Dutch elm disease (DED), this stately tree may be doomed.
The DED is a fungous infection, nearly always fatal, carried by the larvae of a bark beetle. Efforts to combat it over the years have focused on protecting healthy trees with insecticides, controlling the beetle that acts to carrier, curing infected trees with fungicides, and finally, if all else fails, destroying infected trees to retard the spread of the disease. Another approach to the problem has been to develop DED-resistant strains and hybrids of the American elm.
The insecticide methoxychlor is somewhat effective againist the elm bark beetle. The systemic fungicides Benomyl and Lignasan, injected into the trunks of trees in fairly large doses, can protect them from DED infection for about a year.
Most promising are the resistant elms that are now becoming available. The most widely distributed of these, the urban elm, though highly resistant, is an elm in name only; it lacks the American elm's distinctive shape. DED-resistant strains of the American elm are now being distributed to selected nurseries. They may be the means of preserving this shapely tree for posterity. This a beautiful tree and it needs to be protected for future generations and forever in this world. If you do not have an elm tree in your yard its time you planted one.
Dave Mize is the owner of Mize Enterprises at gardencenterplus.com
Source: www.articlecity.com
