A fungal disease causing leaf damage
Anthracnose is a fungal disease that commonly infects ash, oak, maple, and sycamore trees. This infection usually begins in the spring when the new leaves develop. The fungus can attack the buds, leaves, twigs, and branches, causing them to brown or blacken.
Infected trees require chemical treatment for control
Trees with a history of anthracnose infection will require fungicide sprays to prevent the disease. If untreated, infected leaves will often wilt and fall off the tree in mid- to late-summer. Repeated loss of leaves can reduce tree health.
What to look for
• Distorted areas in leaves and irregular patches of leaf discoloration.
• Early leaf drop.
• Blotches along leaf veins.
• Shoot and leaf blight; twig and branch cankers.
• In late fall and early spring, black pimples develop on infected leaves from the previous year.
• Spores are released and blown by wind or splashed by rain to nearby trees.
• The fungus may infect foliage, fruit, and blossoms.
• Primary infections produce secondary infections on other leaves and fruit.
• Secondary infections continue throughout the growing season during wet periods.
Treatment and Prevention
• Increase tree vigor:
– Forest Floor Program
– Puritea Soil injections
• Prune out infected branches (sycamore).
• Water at ground level only; avoid splashing on leaves.
• Plant less susceptible tree varieties.
Fungicidal sprays early in the growing season.