Zeiraphera canadensis

Zeiraphera canadensis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Tortricidae
Genus:	Zeiraphera
Species:	Z. canadensis
Binomial name
Zeiraphera canadensis Mutuura & Freeman, 1967

The Spruce Bud Moth (Zeiraphera canadensis) is a moth of the Tortricidae family.

The larvae feed mainly on Picea glauca but they have been found on other species of spruce and fir.^[1] While it is not a concern in natural stands, in spruce plantations in is considered a pest, as repeated years of defoliation leads to deformity in the crown, loss of stem form and lower productivity.^[2]

Distribution

Mainly in eastern North America, but found across the continent.^[1]

The spruce bud moths of the genus Zeiraphera, transcontinental in range, are found frequently on white spruce but only occasionally on other spruces and firs Rose and Lindquist (1985).^[3] Zeiraphera canadensis Mutuura and Freeman (Lepidoptera: Tortricidae), has caused a high incidence of multiple and abnormal leaders in white spruce in the Maritime Provinces, Quebec, and Maine (Quiring et al. 1991).^[4] However, although severe feeding damage has seldom been extensive in forests, new shoots on open-grown white spruce are frequently disfigured (Rose and Lindquist 1985).^[3] The insect overwinters in the egg stage on the tree. The larva emerges in May and feeds underneath the bud cap, which it characteristically secures to the growing shoot with silk. The cap remains in place long after the other bud caps have been shed, an obvious impediment to the effectiveness of contact insecticides. When populations are high, it is not unusual to find several larvae feeding among the needles of a single shoot. The head and thoracic legs of young larvae are dark brown, but full-grown larvae are cream to yellow and about 10 mm long. Feeding is completed in June or early July, whereupon the larva drops to the ground and becomes a pupa in the litter. From mid-July to mid-August, moths emerge from the pupae to lay eggs singly or in groups of 2 to 7 at the base of shoots of the current year. In a New Brunswick seed orchard, white spruce of intermediate height (1.5 m to 3.73 m) were damaged most, and damage in 1 year was positively correlated with damage in the next. At 4 test sites, mean growth reduction of trees in the 2 most susceptible families was estimated to be approximately 30% higher than those of trees in the 2 least susceptible families. The lack of damage to some trees, among those trees suffering damage, suggested the existence of genetically based differences in susceptibility to this pest.

Life Cycle

Z. canadensis overwinters as an egg on the tree, emerging in May it feeds on developing bud, eating new needles and the developing bark of the shoot.^[1] A characteristic indicator of this feeding is observing the bud cap remaining at the tip of the branch long after the rest have fallen off.^[1] The budmoth secures the bud cap to the developing cap with silk, enablining it to feed securely underneath.^[1] Once feeding is compelete in June/early July, the larvae drops to the soil and pupates in the leaf litter, emerging in July/mid August, where they lay their eggs.^[1]

The mature larvae is 10mm long and creamy yellow.^[1]

References