Adelges abietis

Eastern spruce gall adelgid. Photo: E. Bradford Walker, Vermont Department of Forests, Parks and Recreation, Bugwood.
Scientific Name: 
Adelges abietis
Common Name: 
Eastern Spruce Gall Adelgid
Growing Degree Days (GDD's): 
22-170 GDD's (Source: Cornell Cooperative Extension) and 2000-3000 GDD's (Source: Robert Childs, UMass Extension), Base 50F, March 1st Start Date.
Host Plant(s) Common Name (Scientific Name): 
Black spruce (Picea mariana)
Colorado blue spruce (Picea pungens)
Engelmann spruce (Picea engelmannii)
Norway spruce (Picea abies) *Preferred host.
Red spruce (Picea rubens)
White spruce (Picea glauca)
Insect Description: 

This insect was introduced into North America from eastern Europe some time prior to 1900. Adelgids overwinter as a partially grown female. These females mature into adults (stem mothers) in the early spring and are tiny (1/16 of an inch long). Each female will lay 100-200 oval, brown eggs within a coating of woolly wax. This occurs just around budbreak. Eggs hatch and brown/black nymphs (potentially also coated in wax) feed on the new needles. These nymphs eventually move to feed at the base of the needles, and induce gall development. These galls develop around the immature insects who continue to feed within. During this time, these insects are very well protected from harsh abiotic conditions, predators, and parasites. By late summer, these galls dry out, crack open, and the nearly mature nymphs emerge. Once "on the outside", these nymphs develop into winged females who will lay another crop of eggs coated in white woolly wax, which will hatch into the nymphs who will spend the winter near a terminal twig or dormant bud. The galls created by this insect develop at the basal portion of host plant shoots, weakening the stems to the point where they may more easily break from the weight of snow or other physical stresses.

Damage to Host: 

Creates galls and eventual twig death. Galls have twig growth beyond the gall. This can be a very serious pest over time. It may greatly weaken the host tree and make it very susceptible to secondary pests. An aesthetically displeasing pest on Christmas trees.

Monitoring: 

In the late winter, observe the base of needles for overwintering nymphs covered in white waxy material. Look for the white, waxy coating over eggs laid in the spring and subsequently hatched nymphs which induce the development of green galls. Sticky traps may detect the winged females found at the end of the summer.

Cultural Management: 

Prune out and destroy still green galls when possible if this action does not severely disfigure the tree. Galls that are brown and cracked open have already released the living insects within, and will not reduce subsequent populations through their removal. 

Natural Enemies & Biological Control: 

None reported in the literature for North America. Predacious flies have been observed feeding on this adelgid in its native range in Europe (Cnemodon spp.) and, in Turkey, Leucopis species have been recorded feeding on related adelgids, but little is currently known about the natural enemies of this insect.

Chemical Management: 

Abamectin (NL)

Acephate (NL)

Acetamiprid (L)

Bifenthrin (NL)

Carbaryl (L)

Chlorpyrifos (N)

Chromobacterium subtsugae (NL)

Clothianidin (NL)

Cyantraniliprole (NL)

Dinotefuran (NL)

Flonicamid+cyclaniliprole (N)

Horticultural oil (L)

Imidacloprid (L)

Insecticidal soap (NL)

Pyrethrin+sulfur (NL)

Tau-fluvalinate (NL)

Notes: 

Dormant oil application prior to bud break has been said to be effective. Insecticide efficacy is often considered best in the spring. Late-summer treatments must be timed to the emergence of adults and timing can be difficult.

Active ingredients that may be applied systemically include: abamectin (injection), acephate (injection), acetamiprid (injection), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), dinotefuran (soil drench), and imidacloprid (soil drench).

Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.

Note: Beginning July 1, 2022 neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: https://www.mass.gov/pesticide-product-registration .