Fungus affecting Green Ash trees in Winnipeg
WINNIPEG - JUNE 10, 2005 - Green ash trees in the city are currently under assault from a fungal disease known as anthracnose. The disease (which does not affect humans) infects the trees’ buds, leaves, and twigs and thrives in cool to warm wet weather.
In mild cases of infection, anthracnose is mainly a cosmetic issue affecting the overall appearance of the tree. In cases where the infection is more severe and recurs annually, the trees may lose their ability to effectively produce enough sugar through photosynthesis to maintain good health. This could lead to a state of general decline making the tree more susceptible to other pests.
Symptoms may include: 1) distorted leaves, 2) leaves with irregular brown blotches of dead tissue associated with the veins, 3) late leaf out, 4) premature leaf drop and 5) greenish to dark brown lesions on shoots.
Residents whose trees are affected should promptly rake and discard fallen leaves to reduce disease incidence since the fungus over- winters on infected dead tissue. Infected material should not be placed in composters. Normal watering and fertilizing of trees will help to sustain healthy growth. Residents may also prune out dead or severely diseased branches on their privately owned trees to promote air movement within the crown. Control is difficult when the disease is widespread and trees are visibly damaged. Healthy trees will recover on their own by producing new leaves by midsummer.
Residents who suspect their trees are infected may wish to consult with a professional tree care firm for more information.
Last update: 10.06.2005
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