More Attacks Of Cypress Canker

Press, Volume CIII, Issue 30543, 11 September 1964, Page 6

More Attacks Of Cypress Canker

A trouble which is becoming common is Cypress canker. This disease attacks a wide range of ornamental conifers and one only becomes aware of its presence when a small branch dies out.

This is often accompanied by the formation of a small canker and sometimes by the exudation of gum. The trouble spreads to living tissue until the entire branch is dead and it may often girdle larger branches, or even the trunk, causing the death of all portions above the infected area. Even when this disease is only slight it causes disfigurement of conifer, and where the main trunk is infected it can result in all the uppermost portion being killed. A wide range of conifers are infected, including all forms of Cypress, both species and their varieties, all species of Chamaecyparis and their many varieties, junipers and

Thuja orientalis and its varieties. These conifers vary in their susceptibility to this disease from species to species, and even from variety to variety within a species. The species Chamaecyparis lawsoniana seems to be the most susceptible of that family. Here the species seems to be more prone than its varieties. The varieties “Ellwoodii” and “Potennii” are the most susceptible of all the named varieties. Infection takes place through wounds such as are caused by wind damage, insect pests, pruning tools and clippers. No Control There is no adequate means of control although cultural methods can reduce the incidence of disease. Reduce all damage to a minimum by careful use of tools and a satisfactory pest control. Lightly infected branches should be cut back to healthy wood. All infected trees should be dug out and burnt and any infected material removed. After pruning or clipping, spray the entire tree with Bordeaux or cuprox as this seems to exercise some control. Pruning tools should be disinfected after use to prevent the disease from infecting healthy trees.