Leucostoma Kunzei - Disease Management

Disease Management

Due to older, weakened trees being most susceptible to Leucostoma kunzei, the key factor in proper management of this disease is maintenance of tree health and vigor by reducing stress on the tree. Choose planting sites with good, moist, well-drained soils; avoid shallow or excessively drained soils. During periods of prolonged drought or on dry sites regular watering is important during the growing season, as well as, the application of fertilizers every few years. Well-established trees and avoidance of any disturbance to the root system that may result in root injury or poor root growth both reduce likelihood of individual trees becoming diseased.

Selective pruning of lower branches where possible, without completely destroying the aesthetic appearance of the tree is advisable. On less severely cankered trees, all diseased and adjacent branches should be pruned back to the nearest living lateral branch or the trunk. Weak and injured branches should be cut to the trunk of the tree. On major limbs or trunks the cankered portion may be excised. This may be done by removing all brown, dead tissues, as well as, 1 inch of healthy bark and wood on all sides, cutting to a depth of ¼ inch. Proper sanitization of tools is crucial in prevention of accidental spread of this disease; this may be done by disinfecting them by either swabbing or immersing them in a solution of 70% rubbing alcohol. Pruning during wet conditions can potentially increase incidence of disease spread through pruning wounds; therefore, prune only when the foliage and bark are dry. Severely cankered trees cannot be restored to good health and should be completely removed from the site and if possible, burned to remove the source of inoculum.

To date, there have been no fungicides which have been able to provide prevention or arrest the development of Leucostoma canker on spruce trees