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Acleris gloverana (Tortricidae)
the western blackheaded budworm
Adults:
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The adult is a small, patterned, grey to brown moth. Colour and pattern variations are wide, ranging from a dappled brown, black, orange and white with faint to distinct horizontal bands, to dappled but with a longitudinal yellow, orange or white stripe. The hindwing is a uniform grey or brownish grey.
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Larvae:
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Larvae are bright green to yellowish green with a black or brown head capsule and thoracic shield. At maturity, they are 12 to 16 mm long.
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Damage:
Eggs laid singly on the underside of needles, hatch in early spring and young larvae bore into opening buds. When half-grown, they leave what is left of the bud and construct a loose shelter of clipped needles. Feeding continues on the new foliage until it is depleted and then old foliage is consumed. They are wasteful feeders, leaving partly consumed needles, causing heavily infested trees to have a reddish brown appearance. Because eggs are laid mainly in the upper branches, defoliation is most severe in the upper crown. Outbreaks that persist for two or more years result in much top-kill and some tree mortality.
Principal Hosts:
Preferred hosts are western hemlock (Tsuga heterophylla), mountain hemlock (T. mertsiana) and true firs (Abies spp.). Spruce and Douglas-fir are also attacked.
Economic Importance:
Severe outbreaks, which occurred on the coast during the 1940s and 1950s covered millions of acres and resulted in considerable tree mortality. Since that time, outbreaks have occurred in the interior from '65 to '68 and on Vancouver Island from '70 to '73. Although defoliation extended over vast areas, tree mortality was confined to small patches.
References and Links:
EAG: 487-488; FC: 162; FPL 24.
See HForest or JP17.
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