Usually the leaf blotches develop after most of the tree growth is completed so it does not affect tree health significantly. Usually the disease does not require control. Foliar fungicides applied when the leaves are fully expanded and repeated 10-14 days later will provide good protection if needed. This rust infects the fruit and twigs of susceptible cultivars. The orange colored spores and the white tube-like growths on the fruit are diagnostic for quince rust.
Infected twigs become swollen, distorted, and if girdled can die.
Petioles and thorns can also be infected. Usually the damage is cosmetic with only some small twig death and does not require control. Some cultivars can be severely infected making them very unattractive in the landscape. Hot It is important to prune branches, damaged in Delaware's recent thunderstorm, quickly. Jagged branches that are left behind provide an easy entry for insects and disease organisms.