Cooley Spruce Gall Adelgid

Aldelges abietis, Adelges cooleyi

Cooley spruce gall adelgid and / eastern spruce gall are caused by close relatives of aphids, called adelgids. A plant gall is an abnormal plant tissue growth caused when an adelgid injects a hormone into the tree bud. The gall provides food and shelter for the insect.

Although most galls are considered cosmetic, in the case of cooley spruce gall / eastern spruce gall, they may kill the ends of the branches they infest. A heavy infestation creates tree stress that can lead to more serious problems.

Download Cooley Spruce Gall Adelgid Fact Sheet

Treatment Strategy

Small infestations of spruce galls are not necessary to treat. However, large infestations can disfigure the tree and cause dieback of branches.

The complexity of adelgids' life cycle made management of them especially difficult in the past. However, with new technology using systemic insecticides, this insect is easy to control because sprays no longer have to be timed to the emergence of the young nymphs. The systemic insecticide Optrol™ is effective for cooley spruce gall adelgid / eastern spruce gall adelgid and can be applied at virtually any time of the year, as long as the ground is not frozen or water saturated. The treatment involves mixing Optrol™ in a watering can and pouring it around the base of the tree. If there is mulch or leaf litter present it must be scraped away before application as Optrol™ will stick to these materials and not be available to move into the tree.

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Cooley Spruce Gall Adelgid Treatment Option 1

Optrol™ is applied to the soil and has a long residual (1 year). However, it usually takes 30 – 60 days for the product to reach the leaves. Professional arborists will often apply Optrol™ in the fall for control the entire next season. Early spring applications are also very effective.

Application Type Soil drench

DIY Product/Equipment Needed:

•  Optrol™

Soil Drench Kit

 • Measuring or diameter tape

•  Bucket or watering can

•  Gloves

Cooley Spruce Gall Adelgid Treatment Option 2

Spray products such as Up-Star® Gold are not used very often anymore for larger trees due to issues with drift and contact with beneficial insects. They are, however, still used on smaller plants that are easily treated with a hand sprayer. These products typically have a residual of 10 – 14 days and should be applied to coincide with egg hatch and crawler emergence to be effective.

Application Type Foliar spray

DIY Product/Equipment Needed:

• Up-Star® Gold

• Hand pump sprayer with wand

• Gloves

• Safety Glasses

Cooley Spruce Gall Adelgid DIY Kit

Option 1

Application Type  Soil drench

DIY Product/Equipment Needed:

•  Optrol™

• Soil Drench Kit

 • Measuring or diameter tape

•  Bucket or watering can

•  Gloves

Option 2

Application Type Foliar spray

DIY Product/Equipment Needed:

• Up-Star® Gold

• Hand pump sprayer with wand

• Gloves

• Safety Glasses

 

How Is It Spread?

The lifecycle of the Spruce gall maker takes about one year to complete. Females overwinter on the current years twigs, laying eggs in the spring. Eggs hatch and move to the needle bases to feed and form galls. Nymphs molt three times in the gall and emerge in August and September. These mature nymphs crawl to the needles and molt into winged females. These adults lay eggs and die. The eggs laid become the next years generation.

Susceptible Trees

Colorado and white spruce are common hosts of these gall makers, and they can also affect other spruce and pines. Douglas fir can be an alternate host to this insect, however galls are not formed on these trees.

Symptoms

Spruce galls look like small pineapple-like structures at the ends of twigs. They can either be green if they are new or brown if they are 1 or more years old. These growths are often visible on the tree for up to 5 years after the insects have left them.

Lookalikes

None

Related/Similar Problems

Spider mites

Timing

Spring or Fall

Urgency

Low

Risk of Spreading

Moderate

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