At a Glance
- Apple leaf curling midge (ALCM) is a newly recognized pest in apple orchards in the Okanagan.
- Also known as apple leaf gall midge or apple leaf midge.
- Primarily affects young orchards and rootstock nurseries.
- Damage targets rapidly developing leaf tissue, limiting tree growth.
- Less of a concern in mature, established apple orchards.
- Typically has two to three generations per year; research is ongoing.
Why Is Apple Leaf Curling Midge a Problem?
Apple leaf curling midge (ALCM), Dasineura mali, is a recently recognized pest of apple orchards in the Okanagan. Adult midges are small mosquito‑like flies that lay eggs along the edges of young leaves. As larvae develop, the leaf margins roll inward, forming a distinctive purple‑hued fold.
Most damage occurs on young, actively growing leaves, which means ALCM is most problematic in young orchards and rootstock nurseries, where tree growth can be reduced or delayed. In contrast, the pest is generally less concerning in mature, established apple orchards where new leaf growth is limited.
Where Does Apple Leaf Curling Midge Come From?
Adult ALCM typically lay eggs in the spring, with visible signs of leaf curling becoming evident in orchards after petal fall. It is believed that there are two to three generations per year, although research is ongoing to better understand the pest’s life cycle under local conditions.
Learn More (Video)
Interested in finding out more? Check out the BC DAS Apple Leaf Curling Midge video on YouTube to connect horticultural knowledge from the field with the online DAS program or visit the Tree Fruit Production Guide.