ABSTRACT
Popcorn disease, known to be caused by <em>Ciboria carunculoides</em> (Siegler and Jenkins) Whetzel, was observed on a single white mulberry tree (<em>Morus alba</em> L.) growing in south central Kentucky. The disease was not found on other white or red (<em>Morus rubra</em> L.) mulberries growing nearby. Diseased fruits were significantly (P<0.01) heavier, longer, and wider than normal fruits. On the lower branches, approximately one-half of the berries were diseased, whereas the proportion of diseased fruits de- creased in the higher branches.