Damage to trees and their leaves mostly temporary
A number of the ash trees that line residential streets have been infected by the fungal disease anthracnose, which grows on the ash trees and spreads more during cool, wet springs. They have also been hit by the ash plant bug. Both assailants attack the tree’s leafs, but in most cases the damage is mostly superficial and the tree does not sustain long-term effects. Supplied
If you are walking in some parts of Camrose, it might look like fall has come a few months early.
The City has received numerous calls from residents that ash trees throughout Camrose have been losing their leaves. To blame are two different pests; the fungus anthracnose and the ash plant bug. Around half of the boulevard trees in Camrose are ash trees, so should we be concerned about losing them? City Parks Director Chris Clarkson says “we don’t need to worry; the damage will be temporary and will have more effect aesthetically than on the health of the trees.”
The City takes good care of its trees, which are an important facet of Camrose’s beauty. The tree care regimen includes watering, fertilizer, and pruning that keep the trees healthy so that they are able to survive when problems such as this occur.
A particular strain of the fungal disease anthracnose, Gnomoniella fraxini, grows on ash trees and spreads more in cool, wet springs like the one we just had. As it grows and releases spores, it causes brown leaf spots, distorted leaf growth, and sometimes defoliation. By the time that these symptoms are obvious, it is too late to implement any controls on the fungus.
The ash plant bug is a light green or brown insect five to eight millimetres long with a yellow triangle on its back. The eggs overwinter on the bark of the ash tree and the insects hatch in the spring, puncturing leaves to drink the tree’s fluids and leaving white speckles on the leaf. Heavy infestation will cause the whole leaf to die and fall off.
Fortunately, neither of these two pests normally cause permanent damage to the tree.
Most of our ash trees are mature and healthy, thanks to the City’s care, and are able to withstand the effects of losing their leaves. In fact, they can have a second growth of leaves later in the summer to replace those lost. Most trees are even able to meet their needs with a significant percentage of their leaves missing.
There is a possible danger if severe infestations occur continually over subsequent years that the health of the trees will decline, but the City will monitor this and act accordingly. Chemical controls exist for both pests, but are usually used only on young and weak trees.
What you can do is rake and remove the leaves that have fallen to the ground, helping to break the life cycle of anthracnose and the plant bug to reduce their spread next spring.
If you have ash trees in your own yard, make sure to do all you can to keep them healthy, such as watering, fertilizing, and pruning to remove dead, infected branches and to improve air flow through the canopy to prevent the fungus and insects from becoming entrenched in your trees.
If you have questions about the City of Camrose’s tree care practices, call Community Services at 780-672-9195.
The City of Camrose and the Camrose Wildlife Stewardship Society have tons of events for you this summer.
Come out to the Stoney Creek Centre at 7 p.m. tonight to learn about new advances in solar energy and how you can get involved with Newo, a local startup. Tree planting in the Stoney Creek Valley will occur on the June 19 and 21 at 7p.m. On the June 22 at 7 p.m., join Craig Toth of the Edmonton Beekeeper’s association to learn about urban beekeeping and what you need to do to get started. You will also get to sample different varieties of local honey.
Carson Hvenegaard is the Wildlife and Greenspace Stewardship Coordinator for the City of Camrose. If you have any questions regarding wildlife in Camrose or our great system of parks, contact him at 780-672-0544 or at firstname.lastname@example.org.