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Callidiellum rufipenne

Japanese cedar longhorned beetle adult male and female. Photo: Connecticut Agricultural Experiment Station, Bugwood.
Scientific Name: 
Callidiellum rufipenne
Common Name: 
Japanese Cedar Longhorned Beetle
Growing Degree Days (GDD's): 
None available at this time.
Host Plant(s) Common Name (Scientific Name): 
American arborvitae (Thuja occidentalis)
Atlantic white cedar (Chamaecyparis thyoides)
Common juniper (Juniperus communis)
Eastern redcedar (Juniperus virginiana)
False arborvitae (Thujopsis dolabrata)
Hinoki cypress (Chamaecyparis obtusa)
Japanese cedar (Cryptomeria japonica)
Leyland cypress (Cupressus x leylandii)
Monterey cypress (Cupressus macrocarpa)
Nootka falsecypress (Chamaecyparis nootkatensis)
Sawara cypress (Chamaecyparis pisifera)
Insect Description: 

The Japanese cedar longhorned beetle was first detected in Washington state in 1954. This wood boring beetle is found in conifers belonging to the cypress family. Primary hosts noted for this species include arborvitae, cypress, juniper, and cedar (Chamaecyparis). Adult beetles are small, approximately ¼ to ½ inch in length with long antennae (males have antennae that are slightly longer than their bodies; females have shorter antennae). The females have reddish brown elytra (hardened wings) and the males appear darker in color (shiny blue-black) with red visible on the “shoulders” of the beetle (just behind the thorax). There is one generation per year, although in colder locations it may take 2 years to complete its life cycle. Once the females emerge from their host, they begin to lay eggs in the cracks and crevices of bark during their 20 day life span. Each female lays approximately 20 eggs (Shibata, 1994). Eggs hatch within 2 weeks and the larvae bore beneath the bark, creating tunnels or galleries as they feed in the phloem and cambium layers of the tree or shrub. Larvae are cream colored with 3 pairs of thoracic legs and grow up to approximately ¾ inch in length. As many as 10 larvae may be found in a single arborvitae branch. When the larvae are mature, they enter the xylem where they pupate, which is suspected to occur in the fall. The Japanese cedar longhorned beetle is thought to overwinter as an adult within the host plant, and emerges early the next season in the spring (Hoebeke, 1999; Humphreys and Allen, 2000; Maier and Lemmon, 2000). However, depending upon geographic location, there is discrepancy between sources regarding the overwintering life stage of this insect. Can be confused with the native Semanotus ligneus, cedar tree borer.

Damage to Host: 

The feeding damage from the larvae of this insect causes branch dieback which may not be noticed until the following spring after initial infestation. Other signs of this insect include frass found near galleries and splits in the bark and 1/8 inch, oval exit holes. Bark may appear puckered where larval mining occurs, and frass can be seen within the mines if they are exposed by splits in the bark. Frass-packed galleries occur in the cambium and xylem.

Monitoring: 

Monitor for this insect, especially in Suffolk and Nantucket Counties in Massachusetts. May also be present elsewhere in the state. Look for branch dieback on susceptible hosts in the spring. Look for bark splits, galleries, frass, and oval exit holes. With caution and the proper tools, slice open dying branches to look for galleries in the cambium and xylem and also potentially expose larvae, pupae, or adult beetles. 

Cultural Management: 

Borers may be preferentially attracted to stressed plants. Take precautions to avoid plant stress, such as proper planting and site selection. Prune out and destroy infested branches prior to adult emergence in the spring.

Natural Enemies & Biological Control: 

In Japan, Shibata (1994) determined that approximately 53% of pre-adult Japanese cedar longhorned beetles succumb to disease or parasitism by a suite of natural enemies. Most of the larval mortality occurs due to (as of yet) unidentified diseases; some pupal mortality occurs due to disease as well. Before pupation, larvae are also killed by two important parasitoids - Doryctes yogoi and Ischnoceros sapporensis. Two species of parasitoids from the pupal cells of Japanese cedar longhorned beetles are also known - Baeacis semanoti and Rhimphoctona spp. (Invasive Species Compendium; CABI).

Chemical Management: 

Acephate (NL)

Acetamiprid (L)

Azadirachtin (NL)

Beauveria bassiana (NL)

Chlorpyrifos (N)

Cyantraniliprole (NL)

Dinotefuran (NL)

Emamectin benzoate (L)

Flonicamid+cyclaniliprole (N)

Imidacloprid (L)

Isaria (paecilomyces) fumosoroseus (NL)

Permethrin (L)

Pyrethrins + piperonyl butoxide (L)

Zeta-cypermethrin (L)

Notes: 

Active ingredients that may be applied systemically include: Acetamiprid (injection), cyantraniliprole (soil drench, soil injection), and imidacloprid (soil drench).

When used in a nursery setting, chlorpyrifos is for quarantine use only.

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.

Wood boring damage to arborvitae caused by the Japanese cedar longhorned beetle viewed on 11/21/2023 in Norfolk County, MA. Photo courtesy of Aaron Caswell. Wood boring damage to arborvitae caused by the Japanese cedar longhorned beetle viewed on 11/21/2023 in Norfolk County, MA. Photo courtesy of Aaron Caswell. Wood boring damage including oval exit holes to arborvitae caused by the Japanese cedar longhorned beetle viewed on 11/21/2023 in Norfolk County, MA. Photo courtesy of Aaron Caswell.

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.