trees | Durham Master Gardeners

This is the time of year that owners of Eastern red cedars and apple trees will be on the lookout for a fungal disease known as Cedar Apple Rust.

cedar apple rust

According to OMAFRA’s Publication 310, Integrated Pest Management for Apples,

Symptoms begin to appear at about the same time apple trees are in the pink stage, after a wet period caused by a rain or heavy dew. Galls on the eastern red cedar produce orange telia horns 10-20 mm long that grow from the galls and become orange-yellow and gelatinous.

Symptoms of this rust disease look very different on these two species, but both apple trees and Eastern red cedars (Juniperus virginianae) are affected. This condition can result in complete defoliation and loss of crop.

In apple trees, small, pale yellow spots appear on the upper surface of leaves and on the fruit.

For more information about Cedar Apple Rust, including treatment and management strategies and detailed images of the galls and telia horns on Eastern red cedar, see:

Cedar-Apple Rust and Quince Rust (Ontario Ministry of Agriculture, Food and Rural Affairs)
Cedar Apple Rust (University of Nebraska)

(Photo source: OMAFRA)

The Emerald Ash Borer Comes to Oshawa

Durham Master Gardeners would like to inform the public about an upcoming information session being held in the City of Oshawa regarding the Emerald Ash Borer, an extremely invasive pest that has been killing ash trees and has now arrived in Oshawa.

Educational material will be made available to the public for drop-in on Wednesday, April 4 at:

Civic Recreation Complex
99 Thornton Rd. S.
Room 5
Drop-in 9:00 am until 9:00 pm

According to the City of Oshawa News website,

The EAB infestation in Oshawa is spreading faster then expected. It is important for residents to learn what an ash tree looks like, the signs and symptoms of EAB infestation and what can be done. Property owners play a significant role in preventing the spread of EAB.

The City has prepared a plan to help manage the impacts of EAB on publicly owned lands (along streets, in parks and open spaces). Private tree maintenance is the responsibility of the property owner.

EAB has killed millions of ash trees in southwestern Ontario, and poses a major economic and environmental threat to urban forest in Canada and the United States.

For additional information about the Emerald Ash Borer in Canada, see the Canadian Food Inspection Agency’s fact sheet, Emerald Ash Borer, Agrilus plannipennis

(Image source: Canadian Food Inspection Agency)