Arborvitae leafminer
Argyresthia thuiella (Packard) Lepidoptera: Argresthiidae)
Orientation to pest
The arborvitae leafminer, Argyresthia thuiella (Packard), is a native North American moth that forms mines in foliage of eastern arborvitae (northern white cedar) trees (Thuja occidentalis L.) in forests and landscapes. This moth is found in eastern Canada and in the United States, south to Maryland and west to Missouri. It is also invasive in Europe. Adults fly in spring to early summer and adults lay eggs in the axils of branchlets or along the edges of leaves. Newly emerged larvae bore into the leaves and feed the rest of the year there as leafminers. Winter is passed as larvae in mines and pupation occurs in the mine. Adults emerge the following spring. Outbreaks in Maine have severely damaged arborvitae. Damage can also occur in nurseries or on landscape arborvitae.
Hosts commonly attacked
This caterpillar feeds on eastern arborvitae (northern white cedar) trees (T. occidentalis).
Distribution
The moth is found in eastern Canada and in the United States, south to Maryland and west to Missouri.
Images of arborvitae leafminer
Figure 1. Adult of arborvitae leafminer Argyresthia thuiella (moth wingspan is 8 mm); right, moth in natural pose | Figure 2. Mature larvae of arborvitae leafminer, removed from mine | ||
Figure 3. Mined (brown) arborvitae foliage; right, view of larvae in mine (cut away) | Figure 4. Arborvitae leafminer pupa | Figure 5. View of damage on landscape arborvitae, top, close up; bottom, general view of damaged plant |
Important biological control agents related to this pest species
In Canada, natural control of arborvitae leafminers is provided by the widespread parasitoid Pentacnemus bucculatricis Howard and also by Apanteles bedelliae Viereck. Some 26 species of parasitoids are known to attack this leafminer.
Web links for information on arborvitae leafminer
- Fact Sheet | UMass Extension
From the Massachusetts Landscape, Nursery, and Urban Forestry Program - Diagnostic Fact Sheet | Cooperative Extension of Suffolk County, Cornell University
- IPM of Midwest Landscapes Fact Sheet | University of Minnesota
Articles
- Kurir, A. 1983. On the dispersal and biology of the North American arborvitae leafminer, Argyresthia thuiella Packard (Lep., Argyresthiidae) in Austria. Anzeiger für Schädlingskunde Pflanzenschutz Umweltschutz 56(7): 125-128 (in German).
- Anon. 1983. Cedar leafminers. Argyresthia spp. Insect Identification Sheet, Agriculture Canada (74), 2 pp.