Dutch elm disease (DED) is a fungal infection that has wiped out American elms in most of their natural range in eastern North America. Alberta is one of the last places on earth that host healthy stands of these graceful trees. The deadly Dutch elm disease is spread by one of three closely related beetles [...]
Many animals leave their signs on trees. Squirrels, voles and porcupines may chew off bark for food or medication. Sapsuckers (a type of woodpecker) drill holes in thin-barked trees such as birch to drink tree sap and eat the insects attracted to the ooze. Honeysuckles and other shrubs with shredding bark may be stripped by [...]
This disease of hawthorns and juniper shrubs is becoming more common. The disease requires two hosts to complete its life cycle (Juniper and Hawthorn). The symptoms look very different in the two host species. Key Points Minor infestations may look objectionable but cause little damage to the Hawthorn tree Chemical controls may be possible using [...]
Normally our summers are too dry for the development of Fire blight, but in 2008 our spring and early summer were warm and wet enough to result in rapid spread of the disease. Since then we have seen the disease randomly affect Hawthorn, Mountain Ash, Pear, Crab Apple, Apple and Cotoneaster. This bacterial disease can [...]
This fungal disease affects many Poplar and Aspen species. Both Tower Poplar and Swedish Columnar Aspen are highly susceptible to the disease, which is unfortunate due to the number of these trees in Calgary. Bronze Leaf Disease affects only Poplars but not all poplar species are susceptible. Fungal Spores are transferred by air causing infection [...]
Black Knot Fungus affects Chokecherry and Mayday in Calgary and has been on the upswing the decade. Many trees have been recently removed due to extent of infection. The disease is transmitted through the air which carries the spores to their new host. Pruning to remove the fungus should be conducted when trees are dormant [...]
