Zeiraphera canadensis

Status

NATIVE

DOMESTIC SURVEY

Taxonomy

Zeiraphera canadensis Mutuura & Freeman (Tortricidae: Olethreutinae: Eucsomini)

Common name: spruce bud moth

Adult Recognition

FWL: 5.5–6.5 mm

Head, thorax orange-brown; forewing with ground color orange-brown with irregular black and silver fasciae; there is a distinct pale orange triangular mark at the midpoint of the inner margin in most specimens; males lack a forewing costal fold; hindwing of both sexes dark gray or brown.

Male genitalia are characterized by a reduced uncus; large, lobe-like socii; and broad, curved valvae with a well-developed cucullus. Female genitalia are characterized by a telescopic ovipositor; a funnel-like ostium; and two signa in the corpus bursae of unequal size.

Larval Morphology

The following account is summarized from MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338., in which the species was called Zeiraphera ratzeburgiana.

Mature larva approximately 10 mm in length; width of head approximately 0.8 mm; head dark yellow, with darker lateral pigmentation; thoracic shield, anal shield, legs dark yellow; body paler yellow; anal fork absent; SV group on A1, 2, 7, 8, 9 typically 2:2:2:2:2 but occasionally 2:3:2:2:2 or other combination.

Detailed figures of the larval chaetotaxy are available in MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..

Similar Species

Prior to Mutuura and Freeman (1966)Mutuura and Freeman (1966):
Mutuura, A., Freeman, T. 1966. The North American species of the genus Zeiraphera Treitschke (Olethreutidae). Journal of Research on the Lepidoptera. 5: 153-176., this species was thought to be the widespread Palearctic species Zeiraphera ratzeburgiana (Saxesen), which it very closely resembles. For adults, dissection of the female genitalia is required to make an identification. The corpus bursae of Z. canadensis has two signa of unequal size, whereas the signa of Z. ratzeburgiana are equal in size. Larvae of the two species can be separated by the presence (Z. ratzeburgiana) or absence (Z. canadensis) of an anal fork.

In North America, Z. canadensis can be separated from other species (with the possible exception of Z. vancouverana McDunnough) by its distinctive orange forewings in most specimens.

Distribution

Zeiraphera canadensis is broadly distributed in the northern United States and Canada, from Nova Scotia and Maine west to Washington and Alaska. Records from California and Colorado require verification. 

Biology

The following account is summarized from Pilon (1965)Pilon (1965):
Pilon, J. G. 1965. Bionomics of the spruce budworm, Zeiraphera ratzeburgiana (Ratz.) (Lepidoptera: Olethreutidae). Phytoprotection. 46: 5-16., Turgeon (1985)Turgeon (1985):
Turgeon, J. J. 1985. Life cycle and behavior of the spruce budworm Zeiraphera canadensis (Lepidoptera: Olethreutidae), in New Brunswick. Canadian Entomologist. 117: 1239-1247., Régnière and Turgeon (1989)Régnière and Turgeon (1989):
Régnière, J., Turgeon, J. J. 1989. Temperature-dependent development of Zeiraphera canadensis and simulation of its phenology. Entomologia Experimentalis et Applicata. 50(2): 185-193., and Turgeon (1992)Turgeon (1992):
Turgeon, J. J. 1992. Status of research on the development of management tactics and strategies for the spruce bud moth in white spruce plantations. The Forestry Chronicle. 68(5): 614-622..

Zeiraphera canadensis undergoes a single generation per year. In New Brunswick, eggs are laid singly or, rarely, in groups of up to 20 in late July and early August between the scales at the base of the current year’s growth. Eggs overwinter and subsequently hatch in May as white spruce buds begin to burst. First and second instar larvae mine newly needles of newly burst buds. Third and fourth instar larvae feed on the basal end of needles as well as on meristematic tissue, leaving a characteristic scar. The feeding damage caused by older larvae can severely weaken and destroy stems. There are a total of four instars. After completing development in June, larvae drop to the ground to pupate. Adults eclose approximately two to three weeks later and are active for a similar length of time.

Zeiraphera canadensis is a major pest of spruce in North America, especially of young trees in plantation settings. The preferred host is white spruce (Picea glauca), but it will also feed on black spruce (Picea mariana), balsam fir (Abies balsamea), and other Pinaceae. It has not been recorded utilizing pine (Pinus spp.).

Plant Associations

View full screen host table here

Links

Additional photos and a distribution map of this species in North America are available at Moth Photographers Group.