What is Anthracnose, and what can we do about it?
Our SLC Urban Forestry team has recently been hearing from many residents who have concerns about our Sycamore and London Plane trees. These species are affected by a fungal-caused disease called Anthracnose (Apiognomonia spp.) as shown above in an infected London Plane tree. Salt Lake Valley has been benefitting from cooler temperatures and wetter springs. While cool, wet weather sounds great in our arid climate, these conditions can cause Anthracnose to thrive. This fungal disease overwinters in the buds, twigs, fruit, and fallen leaves of affected trees. Anthracnose spores can be spread through air and water when temperatures are between 50-68° F. Rainy weather causes these fungal spores to spread from one infected leaf to another. Symptoms of this infection are new leaves that wilt and drop off the tree in early spring, which can cause canopies to look thin.
In the past, Urban Forestry has attempted to treat infected Sycamore and London Plane trees with methods such as trunk injection and soil treatments. While we have not noticed any major improvement with these treatments, we are currently evaluating new and improved techniques to determine the best treatment for these species.
Fortunately, when temperatures increase, and the rain stops, Anthracnose will become inactive. With the fungus becoming inactive, trees will begin to push out a new flush of healthy foliage. We are beginning to see the canopy of these species starting to fill in as we get into our warmer season. Residents can help prevent the spread of this infection by raking up and removing dead leaves around your tree. We also encourage you to reach out to Urban Forestry to prune away any cankers or dead limbs on city-owned trees.
The best method of helping your park strip tree is by providing plenty of water. Even large established Sycamore and London Plane trees will benefit from deep-root watering. It is recommended that your tree be given 5-10 gallons of water per inch of trunk diameter around 2-3 days per week. Residents are also welcome to apply for a permit if they have a Plant Health Care Arborist who would like to treat their park strip tree with a fungicide.
We appreciate having a great community committed to caring for our Urban Forest. It takes all of us to help preserve the assets we have and ensure that these trees are here for years to come. Thank you to everyone who has reached out to us and brought this issue to our attention. For any additional information, please contact Urban Forestry at urban.forestry@slcgov.com or (801)972-7818
