Abstract

Van Alfen, N. K., and G. S. Walton, 1974. An evaluation of the Lowden formulation containing nystatin for Dutch elm disease control. Plant Disease Reporter 58: 924-926.

A new treatment for the cure of Dutch elm disease is being widely advertised throughout New England. The treatment, containing the antibiotic nystatin, is sold by Lowden, Inc., of Needham, Mass. The nystatin, after being dissolved in a special formulation developed by Lowden, Inc., is injected into trunks of elm trees by use of a gravity flow apparatus. In cooperation with Lowden, Inc., we have evaluated the ability of their fungicide formulation to control Dutch elm disease in experimental plantings of elms.

Our data show that when treatment and inoculation occurred on the same day, significant control of Dutch elm disease occurred as compared with the trees that had not received nystatin. When treatment was delayed for 7 days after inoculation with the fungus, however, there was no control of the disease. Evidently, once the fungus becomes established, the treatment is unable to prevent its spread throughout the tree.

Even more interesting are the data which show that treatment with nystatin 7 days prior to inoculation with the fungus was not effective in protecting the trees against Dutch elm disease. The lack of protection provided by the treatment is not surprising considering the reported instability of nystatin.

The ability of the Lowden formulation to cure established infections could not be demonstrated in our experiments.

Butler, J.D. and B.T. Swanson. 1974. How snow, ice injury affects different trees. Grounds Maintenance 9 (10): 29-30, 40.

Injury to trees from ice, snow, low temperature, wind, or a combination of these is often devastating. Ice injury is often severe regardless of whether or not a tree is in leaf. Serious tree injury from heavy snow is normally restricted to deciduous trees in full foliage. Low temperature injury may result only in the death of buds and small branches, or it may be severe enough to cause the death of large branches or an entire tree.

In October, 1969 and September, 1971 severe early winter storms struck along the Front Range in Colorado. During the storm of 1971 from 15 to 24 inches of wet snow fell on trees in full foliage, and the temperature dropped to 18-24°F. Although the storm was devastating to the landscape, it did present an opportunity to study the performance of urban trees under adverse weather conditions.

Many different kinds of trees were surveyed following the storm. Eleven representative kinds of trees are discussed here. The trees assayed in this study were located in home lawns, along city streets, on a golf course, in a cemetery, and in a small nursery.

Most of the physical injury to trees and shrubs was apparent immediately following the storm. Physical breakage and injury were species, size, and shape dependent, and often reflected past maintenance practices. The data cited here are averages and some trees suffered little or no damage while others were almost totally obliterated. Even so the accumulated information should help in making decisions on what to grow, how much canopy loss to expect under similar situations, and even serve as a basis for clean-up estimates.

• © 1975, International Society of Arboriculture. All rights reserved.