Author: (Saxesen, 1840)
Spruce bud moth
Ratzeburg tortricid
Species Overview:
Adult: 12-15 mm wingspan; forewing ground colour white, suffused with ochreous and grey, with indistinct darker strigulation and tawny brown markings, marked or strigulated with blackish. Basal patch sharply angulated, approaching the median fascia to enclose a nearly triangular blotch of ground colour. Hindwing grey.
Egg: deposited on the inner side of bud scales at the base of the youngest shoots or under lichens.
Larva: head and prothoracic plate light reddish brown; abdomen whitish grey to yellowish green, translucent; pinacula unusually large, dark brown; anal plate light reddish brown; anal comb present; thoracic legs black.
Pupa: 7 mm long; light yellowish brown; frons narrow and convex between antennae; abdominal segments 2-7 with two transverse rows of spines oriented backwards (spines of caudal row smaller than those of anterior row); segments 8-9 bear single rows of spines. The anal segment bears four pairs of thick hooked bristles dorsally and 1 pair ventrally. Spun up amongst leaf litter on the ground. In a flimsy cocoon spun up amongst leaf litter on the ground.
Taxonomic Description:
Male:
Zeiraphera ratzeburgiana adult
Zeiraphera ratzeburgiana adults
External characters: 12-15 mm wingspan. Forewing narrow, without costal fold; termen slightly convex. Ground colour white, suffused with ochreous and grey, with indistinct darker strigulation; markings tawny brown, marked or strigulated with blackish; basal and sub-basal fasciae forming a large, somewhat diffuse, strigulated basal patch, often suffused with grey or grey mixed with whitish, its outer edge sharply angulated at middle and almost touching median fascia to enclose a subtriangular blotch of light ground colour on dorsum; median fascia oblique, poorly defined with edges rather diffuse, confluent with pre-tornal marking, usually with a thick supramedian dash; tornal and subterminal fasciae variable and often indeterminate, usually confluent and forming a small patch sprinkled with blackish in upper part of distal area; cilia grey, apices whitish, a fuscous or black sub-basal line, variably interrupted by whitish dashes. Hindwing grey; cilia paler, with a dark sub-basal line (Bradley et al., 1979).
male genitalia Z. ratzeburgiana
Genitalia: Uncus rudimentary; gnathos absent; socii large and curved outward. Valva without clasper. Basal projection of valva biramose. Ventral margin of valva without notch before cucullus. Apex of cucullus rounded, not narrowing distally.
Female:
External characters: Similar to male.
female gen. Z. ratzeburgiana
Genitalia: Ovipositor telescopic; apophyses long; eighth tergite partially membranous; sterigma strongly reduced, represented by aciculate patches of membrane; antrum well sclerotized; cingulum situated posterior to middle of ductus bursae; two signa present in corpus bursae.
Variation:
Minor variation is found in the intensity and development of the forewing markings. In strongly marked specimens the fasciae may be dark brown with heavy blackish strigulation, the tornal fascia being well developed and separated from the subterminal fascia which is reduced to a stria along the termen (Bradley et al., 1979).
Biology:
Moths fly in July and August, briefly leaving the shelter of trees if disturbed from rest during the day. At sunset it flies around the higher boughs. Females deposit their eggs on the inner side of the bud scales at the base of the youngest shoots or under lichens. The eggs hibernate and hatch in April and May, when buds are opening. Larvae penetrate into the buds and feed on the needles and eventually on the growing point. Needles are tied to the scales of the buds. The web on the needles keeps the outer scales attached to the buds for longer than normal. Malformation of the bud causes the young shoot to bend which severely damages the growing point. Larvae can also attack the female blossom and damage the young cone. Pupation occurs in June and July, in a flimsy cocoon spun up amongst leaf litter on the ground, and lasts 3-4 weeks (Bradley et al., 1979; Bovey, 1978).
Host plants:
Picea abies is the primary host. Also recorded from Picea sitchensis, Picea smithiana, Pinus sylvestris, Pinus pinea and Abies cephalonica.
Damage:
Z. ratzeburgiana damage on Picea abies.
Zeiraphera ratzeburgiana is a pest of secondary importance.
Larvae penetrate into the buds and feed on the needles and eventually on the growing point. Malformation of the bud causes the young shoot to bend which severely damages the growing point. Larvae can also attack the female blossom and damage the young cone.
Distribution:
Northern and Central Europe to Eastern Russia.
Records of Zeiraphera ratzeburgiana in North America refer to Zeiraphera canadensis.
Pheromone:
Pheromone unknown.