Most damage occurs in spring. During wet weather spores are released which may splash or be windblown onto newly emerging tender leaves where they germinate in the moisture and infect the leaf. Overhead watering can also provide prolonged wet periods that are ideal for spreading leaf spot diseases. Integrated Pest Management Strategies 1. Live with the disease.
Most trees tolerate leaf spots with little or no apparent damage.
A tree affected early in the year will re-leaf and the new leaves may not be affected. Only if defoliation occurs several years in a row will most established plants be adversely affected. Remove infected leaves and dead twigs. Raking up and disposing of infected leaves as they drop and pruning out dead twigs can help control the disease by removing spores that can reinfect the new leaves. This is not a cure but can limit infection.