Our ID Notes may contain important tips necessary for distinguishing this gall from similar galls and/or important information about the taxonomic status of this gall inducer.
The plant-feeding gall midges of North America
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Alnus (alder)
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Folded leaflet...Dasineura sp.
Young leaves are folded in half along the long axis. Larvae spin cocoons in the folds and pupate there. Host: A. rubra. Distr.: British Columbia to Oregon.
Unless noted otherwise in the ID Notes, observations of this gall are collected in the Observation Field Gallformers Code with value alnus-fold-gall on iNaturalist. You can view them here: