Choristoneura fumiferana

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Superorder	Holometabola
Order	Lepidoptera
Superfamily	Tortricoidea
Family	Tortricidae
Subfamily	Tortricinae
Tribe	Archipini
Genus	Choristoneura

Scientific Name

Choristoneura fumiferana

Common Name

spruce budworm

Author:Joseph LaForest, University of Georgia

Distrubution

Spruce budworm was first reported in the United States occurred in Maine in 1807. There have been continued infestations throughout the Eastern United States and Canada with Maine, New Hampshire, New York, Michigan, Minnesota, and Wisconsin being affected the most.

Host Range

Balsam fir, red spruce, white spruce, and less commonly other conifers.

Identification

Mostly greenish gray body with distinct, pale subdorsal spots; variable color on head and prothoracic shield. Dark brown head; yellowish brown prothoracic shield with various dark marks and with greenish gray anterior margin. Greenish gray of upper two-thirds of body contrasts with greenish yellow of lower one-third. Pair of offset, yellowish white subdorsal spots on most segments; single pale spot above and below each abdominal spiracle. larvae can grow to be up to 22 mm (3/4 inch) long.

Life Cycle

Typically one generation (some populations with 2-year life cycle). Recently hatched, tiny caterpillar overwinters in silken shelter under bark or in another protected area. Mature caterpillar present from May to July.

Plant Response and Damage

This caterpillar is the most destructive insect in many northern coniferous forests. In spring, the young caterpillar mines old needles, buds, and male flowers. The final two instars eat expanding buds or new foliage as they make webs that often bind the developing shoots together. After a caterpillar consumes all of the new needles, it will eat mature foliage. The spruce budworm and the pitch pine budworm, Choristoneura pinus maritima, are variable in color and sometimes cannot be identified to species without knowledge of the food plant.

Management Approaches

Cultural Methods

Outbreaks are favored by the presence of mature or overmature stands of balsam fir. Where large stands of balsam fir are present, management of the number of mature trees will help control the population of this pest.

Biological Control

Several biological controls are found in the population including four viruses, a microsproidian fungus (Perezia fumiferanae), and a bacterial pathogen (Bacillus thuringiensis) have been evaluated for field control of the larvae, however, the viruses and fungi were not able to provide adequate control. The bacterial agent was effective at protecting foliage in moderate populations (50 larvae per 18 inch branch) but was not effective during extreme outbreaks (8,000 egg masses per 100 square feet of foliage).

Chemical Control

When applied against early instars effective foliage protection can be achieved. Local extension agents, state foresters, or the USDA Forest Service, should be consulted for further details before applying insecticides for budworm control. Special care must be taken when treating infested stands near streams and lakes or other environmentally sensitive areas.

Gallery

References

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