What are the brown corky spots on my apples?
Apple scab is a fungus disease that starts with infections during rainy periods between the time that green leaf tissue begins emerging from apple buds until about two weeks after blossoms fall from the tree. The fungus infects leaves and fruit. Scab-resistant apple cultivars are available.
For small orchards, removing all fallen leaves in the autumn or in the early spring prior to bud break reduces the number of overwintered apple scab spores in the vicinity of the orchard. Leaf litter can be reduced by shredding with a mower to accelerate decomposition. While leaf removal reduces the need for fungicide protection of susceptible cultivars, it does not eliminate it. For optimum protection, fungicides need to be in place on fruit and foliage before rains during spring scab infection periods. If the first generation infections are prevented, then summer protection is not required. If the initial infections do take hold, then continued protection until harvest will be needed to prevent further spread to additional fruit. Contact your local Extension office for fungicide options.