Birch casebearer

Coleophora serratella (L.) (Lepidoptera: Coleophoridae)

Orientation to pest

Birch casebearer, Coleophora serratella (L.), is a European moth that is invasive in North America and is associated with birches (Betula), alders (Alnus), and elms (Ulmus). High densities sometimes defoliate birches, and this insect is considered one of the most important pests of birch in some parts of Canada such as Newfoundland. Because of misapplication of names, literature records from 1938 to 1972 under this name very likely do not refer to the true C. serratella as described here. The adult appears in late spring. Eggs are laid on host leaves and the larva feeds by inserting its head into small mines that it creates. The larva constructs a protective case, which it drags with it as it moves around to feed. Pupation occurs in early summer, and occurs in the larval case, which is fixed to the upper surface of a leaf in a sunny situation.

Hosts commonly attacked

Birch casebearer feeds on birches (Betula), alders (Alnus), and elms (Ulmus).

Distribution

Birch casebearer is found in the northeastern United States, eastern Canada from Newfoundland through southern Ontario into Manitoba, and in western Canada, in British Columbia.

Images of birch casebearer

Ian Kimber 768x512	Thérèse Arcand - Natural Resources Canada, Canadian Forest Service 768x512	Thérèse Arcand - Natural Resources Canada, Canadian Forest Service 768x512	Claude Monnier - Natural Resources Canada, Canadian Forest Service 768x512
Figure 1. Adult birch casebearer	Figure 2. Several larvae (in cases) of birch casebearer on young white birch leaf	Figure 3. Larva of birch casebearer, with the case removed	Figure 4. White birch defoliated by birch casebearer

Important biological control agents related to this pest species

Natural enemies of birch casebearer have been studied Quebec and Newfoundland, and as many as 38 species of parasitoids attack this invasive species there. In the native range (central Europe) 25 species are reported associated with this case bearer. Some of these species (e.g., Campoplex borealis (Zett.) and Apanteles coleophorae (Wilk.), Apanteles mesoxanthus Ruschka, and Apanteles cornvinus Reinh. have been released in North America, but there are no records of their establishment.

Web links for information on birch casebearer

• Fact Sheet | Natural Resources Canada

Articles

• Pschorn-Walcher, H. 1980. Population fluctuations and parasitisation of the birch-alder casebearer (Coleophora serratella L.) in relation to habitat diversity. Zeitschrift für Angewandte Entomologie 89 (1): 63-81. (in German)
• Guevremont, H. and J. Juillet. 1975. Parasites of the birch casebearer, Coleophora fuscedinella [= Coleophora serratella] Zeller (Lepidoptera: Coleophoridae), in the Sherbrooke region, Quebec. Phytoprotection 56 (1): 1-17. (in French)