DESCRIPTION: Aceria ulmicola is a gall mite that causes numerous pustule galls to form on the upper leaf surfaces of certain species of Elm. The galls are concolorous with the leaf but they do tend to redden when exposed to the sun. The mites pass the winter in the crevices of bark and are ready to attack the following years growth as soon as it appears. DISTRIBUTION: Frequent and found from late spring onwards. HABITAT: Found on the leaves of English Elm and Small-leaved Elm.
Back to Gallery