Cedar Apple Rust has been spotted in the Edmonton and St. Albert region of the province.
Cedar Apple Rust is a fungal disease that grows to look like the mass in the photo above. It may look like orange gobs as it grows, but when first starting it appears as orange coloured masses on branches, growing to gobs (galls), and cone-like masses. Junipers and cedars are hosts and while the fungal disease does little to these evergreens; when it spreads to rosaceous plants, ie. hawthorns, apples and mountain ash; the results can be extensive damage. The fungus spreads through the air, little spores leaving the host and affecting susceptible trees previously mentioned. On these trees, the hawthorns, apples and mountain ash, small orange spots appear on the leaves. These spread, grow larger and result in loss of foliage and deformed fruit.
|Clemson University - USDA Cooperative Extension Slide Series, www.ipmimages.org|
The best method of prevention is to prune out any orange masses on junipers and cedars immediately to prevent it spreading to susceptible species of trees. There is no chemical control at this time, though it is recommended to spray Copper Bordeaux Spray on the rosaceous trees on your property as a preventative measure should you spot this rust on host plants. This offers a little protection, but is not a means of eradicating the fungus. The best method is prevention, cut it out and destroy.
To find out more about Cedar Apple Rust, visit Kansas State University for their PDF document on Juniper Diseases.