These spots may turn white as spores are produced. Later in the season, the lesions turn brown and begin to appear on the upper surface of the leaf. Heavily infected leaves drop earlier than healthy ones in the fall. Downy spot survives the winter in fallen leaves. Spores are released prior to budbreak.
Downy spot begins in the lower parts of the tree and spreads upward.
Unfortunately, Schley and Western are highly susceptible to pecan scab and Success and Western are susceptible to shuck dieback. Remove and destroy fallen leaves. Brown spot is found primarily in neglected orchards in areas that have abundant rainfall or high humidity. Primary lesions develop on the lower leaf surfaces as small dots, which enlarge and become reddish-brown with a gray cast. Brown spot may defoliate the tree by October if steps are not taken to control it.