I. Introduction: Although uncommon, incidence of X-spot as high as 86 percent was reported on unprotected 'Golden Delicious' and 'Rome Beauty' fruit in 1950. Other susceptible cultivars include 'Jonathan', 'Stayman Winesap', and 'York Imperial'.

II. Symptoms: The names X-spot, X-rot, and Nigrospora spot have been applied to a small, circular, depressed, necrotic spot typically on the calyx end of apple fruit in the mid-Atlantic region (photo 2-43). A fungus has been associated with X-spot lesions, but the typical lesion symptom has not been duplicated by controlled inoculation.

III. Disease Cycle: The identity of the causal organism has not been confirmed and the disease cycle has not been resolved.

IV. Monitoring: Symptoms of this minor disease appear late in the season on susceptible cultivars such as 'Golden Delicious', 'Rome', 'Jonathan', 'Stayman Winesap' (photo 2-43), and 'York'. Infection may occur from July to September. Observe 25 apples on each sample tree for the presence of this disease where there has previously been a problem.

V. Management:  Fungicides applied for summer diseases provide effective control of X-spot.

Text prepared by K.S. Yoder

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