Spruce bud moth
Needle, Annual shoot
Damage, symptoms and biology
Scouting for the spruce budmoth can be done by observing two different signs:
- the prolonged presence of the bud cap, held by silk threads at the tip of the annual shoot;
- the presence of multiple leaders and branches with many branchlets in the upper crown.
Needles chewed along their margins, or cut off at the base, gradually take on a reddish colour. Although the caterpillars primarily attack apical shoots without any serious consequences during their early development, older caterpillars cause more damage since they are especially fond of the tender bark of twigs, and this leads to shoot breakage during rainfall or heavy winds.
Life cycle (East of the Rockies)
A native species in North America, the spruce bud moth was first reported in 1938, in Eastern Canada. Associated with the spruce budworm during the drastic outbreak of 1939 to 1958, the spruce bud moth’s presence is very noticeable. The damage it causes is often confused with that wreaked by the spruce budworm. However, Zeiraphera canadensis differs from the spruce budworm in that it prefers to feed on open-growing spruce rather than spruce in forests.
Canadian Forest Service Publications
Diet and feeding behaviour
: Feeds on the leaves of plants.
- Webworm: Spins a silk shelter in which to hide or feed.
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