Where does the fungus causing apple scab primarily overwinter?

The fungus that causes apple scab primarily overwinter on dead leaves that have fallen to the ground. During the winter months, these infected leaves remain in the leaf litter, where the spores can survive until spring. When conditions become favorable in the spring, the spores can be released by the decaying leaves, particularly when there are wet conditions, and can then infect new, healthy foliage on apple trees.

While other locations are also considered for various plant pathogens, in the case of apple scab specifically, the significant role of dead leaves as an overwintering site is critical to understanding its lifecycle and management. This knowledge is useful for effective integrated pest management practices, including sanitation measures where removing fallen leaves can reduce the risk of infection the following growing season.