Anthracnose

Hosts, Symptoms & Signs

• sycamore, maple, oak
• all three species show irregular-shaped necrotic lesions on leaves often on veins or on the margins
• on sycamore, new shoots show wilting and dieback
• cankers can develop on branches and trunk
• clusters of dead and live branches may form “witches’ brooms” from repeated dieback
• premature leaf drop late spring/early summer on maple and oak
• dieback of newly emerging shoots and expanding leaves on oak

Disease Cycle

• overwinters in buds, twigs, fruit, fallen leaves or petioles depending on host and anthracnose species
• spores are water- or air-dispersed during leaf expansion, especially during spring rains when temperatures are 50-68 degrees F
• infected leaves can spread disease to other leaves during rain events throughout the growing season

IPM Recommendations

• Manage trees to improve or maintain overall health.
• Rake and destroy fallen leaves to remove overwintering inoculum.
• Prune out dead branches or branches with cankers.
• Water and fertilize as necessary to maintain tree vigor.
• Apply preventative fungicides before leaf buds open, then every 10 to 14 days until disease conditions become unfavorable.