{"id":33617,"date":"2025-07-01T09:50:47","date_gmt":"2025-07-01T13:50:47","guid":{"rendered":"https:\/\/extension.umaine.edu\/publications\/?page_id=33617"},"modified":"2026-01-12T12:17:15","modified_gmt":"2026-01-12T17:17:15","slug":"5048e","status":"publish","type":"page","link":"https:\/\/extension.umaine.edu\/publications\/5048e\/","title":{"rendered":"Bulletin #5048, Balsam Gall Midge (Paradiplosis tumifex) in Maine"},"content":{"rendered":"\n

Bulletin #5048, Balsam Gall Midge (Paradiplosis tumifex) in Maine (PDF for printing)<\/a><\/p>\n\n\n\n

By Brett Johnson, Assistant Extension Professor, Sustainable Agriculture and Farm Business Management Educator, University of Maine Cooperative Extension<\/em><\/em><\/p>\n\n\n\n

For information about UMaine Extension programs and resources, visit extension.umaine.edu<\/a>.<\/strong>
Find more of our publications and books at extension.umaine.edu\/publications\/<\/a>.<\/strong><\/p>\n\n\n

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\"Balsam
Photo: Ronald S. Kelley, Vermont Department of Forests, Parks and Recreation, Bugwood.org<\/em><\/figcaption><\/figure><\/div>\n\n\n

Introduction<\/strong><\/strong><\/h2>\n\n\n\n

The balsam gall midge (Paradiplosis tumifex) is a pest of balsam fir trees and is considered to be an economic pest of Christmas tree plantations in Maine. It is found throughout the range of its principal hosts, balsam fir (Abies balsamea<\/em>)  and Fraser fir (Abies fraseri<\/em>). Economic injury is inflicted in the form of unsightly galls which develop in the current year’s growth as a result of feeding by the larval stages (Fig. 3<\/em>). Marketability is further reduced by the premature dropping of galled needles during current and subsequent years making control of this pest critical in the years leading up to market (Fig. 4<\/em>).<\/p>\n\n\n\n

Biology<\/strong><\/strong><\/h2>\n\n\n\n

The life cycle of the balsam gall midge begins when adult female midges emerge from the thatch of the plantation floor, take flight, mate, and lay on average 120 eggs in the bud scales of newly developing shoots (Fig. 2<\/em>). These eggs hatch in 2\u20133 days. The hatched first instar larvae settle on the needle and immediately begin feeding. In response to feeding, cells in the needle elongate and divide, quickly enveloping the larva in the newly forming gall. Larvae feed throughout the spring and summer, undergoing periodic molting as they develop into their second and third instar forms. The larvae then exit the gall in September and overwinter in the thatch of the plantation floor. In the spring, larvae pupate, undergo a complete metamorphosis, and emerge as adults. The winged adult\u2019s mate and the female again lays eggs, completing the life cycle (Fig. 1<\/em>).<\/p>\n\n\n