Tree Diseases in Our Area: How to Identify and Treat Them, with Laura Roy

September 10, 2025
At first the news from Laura Roy was not encouraging. An accomplished arboriculturalist, she has generational knowledge of our region’s trees, groves, orchards, and plantings. The 18 people gathered in the Duckworth Barn listened carefully as she shared what she is seeing. Increasingly, non-native beetles, bacterial diseases, and fungal infestations are infecting and often killing many of our favourite native species. Nearly gone are native elm and black ash; white ash is at risk from emerald ash borer; and hemlock may only survive provided each tree receives an (expensive) injection treatment. So it’s important to recognize the signs of what is most harmful to the species at hand: our spruce, fir, birch, maple, oak, and apple trees. In her talk, Laura helped us identify a multitude of issues and offered advice on how to treat them — either on our own or with the help of experts in tree care.  (See PDF of her presentation here).

The good news is that with ongoing attention you can support your most-loved trees as they adapt to climate change, diseases, and harms yet to come this way. Healthy trees are impressively resilient and can live 100 years and often much longer. To encourage tree health, Laura recommends each fall you insert fertilizer stakes into the soil around their root flares. Applying dried seaweed mixed with compost is another method of improving soils around their trunks. The logic of aggressive branch thinning, she explained, is that “Apple trees need air to breathe” and be healthy. To resist blights and leaf fungi there are natural spray treatments, like copper, and Neem for the trunk and base area.  

But certain fungi and bacterial diseases are fast and fatal, and as soon as confirmed, it’s often best to remove the tree and prevent further spread by ensuring that its wood and leaf litter gets burned, not mulched. It turns out blended mulch from unmanaged sources, like in Lunenburg and Bridgewater, is how many diseases are spread. Of the many questions she fielded, Laura noted that many native species are doing fairly well thus far, including grey and yellow birch, white pine, mountain ash, oak, most maples, and yes, most apple trees. (Although now, fire blight is emerging for those, so pay attention!) Laura’s professional knowledge and personal concern for everything tree-related was warmly applauded by all who attended. Her service, Mayfair Tree Care, was established in 1972 and is based in Pleasantville, NS.
— David Peters, KCA Environment Committee