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Otiorhynchus ovatus

Adult strawberry root weevil. Photo: Pest and Diseases Image Library, Bugwood.
Scientific Name: 
Otiorhynchus ovatus
Common Name: 
Strawberry Root Weevil
Growing Degree Days (GDD's): 
None available at this time.
Host Plant(s) Common Name (Scientific Name): 
Arborvitae (Thuja spp.)
Blackberry (Rubus spp.)
Blueberry (Vaccinium spp.)
Eastern white pine (Pinus strobus)
Hemlock (Tsuga spp.)
Juniper (Juniperus spp.)
Raspberry (Rubus spp.)
Red pine (Pinus resinosa)
Scotch pine (Pinus sylvestris)
Spruce (Picea spp.)
Swiss mountain pine (Pinus mugo)
White spruce (Picea glauca) *Larval host.
Insect Description: 

The strawberry root weevil is one of several species in the same genus that are injurious to broad-leaved evergreens and yew, among other hosts. The strawberry root weevil is often considered more of a garden pest. Adult strawberry root weevils are the smallest of some of these related beetles. Adult strawberry root weevils can be 4-6 mm in length and are often a shiny black or dark brown in color with long, elbowed antennae. The black vine weevil (Otiorhynchus sulcatus), in the same genus, is perhaps considered to be a more important pest of woody ornamental plants. However, there are records of conifer nurseries suffering notable damage from the activity of the strawberry root weevil. Adult black vine weevils are similar in color, and up to 10 mm in length. A third species, the rough strawberry root weevil (O. rugostriatus) is in between the size of the black vine weevil and strawberry root weevil, with their adults measuring 7-9 mm long (also similar in color) (Johnson and Lyon, 1991). None of the multiple species of root weevil in the United States are considered to be native. Introductions of these species have occurred from Europe, northern Africa, and parts of Asia. However, there is some question about the origins of the strawberry root weevil in the literature. This insect was first recorded in a collection from Massachusetts from prior to 1852. There is some question in the historical literature regarding whether or not the strawberry root weevil originated in Europe (Cacka, 1982).

Adult strawberry root weevils have a rounded abdomen and a relatively short snout for a weevil. In the summer months, particularly August, the adult weevils may become a nuisance in homes if a large population is in the area. However, these insects cause no damage to the home or stored food and can be removed by vacuuming them up. Adults cannot fly, but crawl to disperse (their elytra are fused together). Adults may drop from their host plant to the ground if startled. Adults lay 150-200 eggs in the soil near their host plants, particularly near strawberry. Adults have been observed feeding from 37.4°F to 91.4°F and laying eggs between 64.4°F to 86°F (Umble and Fisher, 2002). (An optimum range of 69.8°F to 80.6°F may exist for egg laying.) Adults are parthenogenetic and nocturnal. Larvae hatch from the eggs in approximately 10 days. The larvae of the strawberry root weevil feed on the bark on roots as well as the root collars of small seedlings or transplants. On arborvitae, adult strawberry root weevils feed on new foliage and may girdle stems. When not found on certain ornamental plants, these root weevils are found on wild or cultivated strawberry or brambles. Larvae are curved, whitish in color with a light brown head capsule, legless and up to 1/4 inch in length. Multiple life stages are said to overwinter, depending upon geographic location. This occurs in a protected area, such as the soil, plant debris, or in homes. The exact timing of their life cycle in MA may not be fully understood. Pupation can occur in the spring, with adults emerging in May or June. In strawberry crops, overwintered adults may become active in May. In Oregon (on peppermint), the strawberry root weevil was observed emerging as an overwintered adult from late May to late July. By late July, egg laying occurred. Larvae were present near the host (in this case, peppermint) all year and were most prevelant from late August until mid-May the following season. Pupation occurred from early to mid-May and continued until late June  (Cacka, 1982). A single generation occurs per year.

Damage to Host: 

The strawberry root weevil may feed upon the foliage of hemlocks and arborvitae as an adult. Notches are eaten from the edges of leaves and typically economically significant damage does not occur from the adult life stage; however, this can be a sign of this pest's activity and the potential for damage to the root area in subsequent seasons. Larvae feed on the roots of their hosts (including strawberry) and cause most of the damage; in the case of ornamental plants, this may primarily occur with hemlocks. The strawberry root weevil may often be considered of primary importance as a pest of nurseries - typically, the most damage is done to seedlings or transplants. This weevil is often not detected until the larvae are mature in the spring and have done most of their damage.


Visually monitor for signs of the activity of this insect. Signs include canopy decline, notched edges of the leaves from adult feeding, root collar damage and bark removal, or the adult weevils themselves (active at night). 

Cultural Management: 

Sticky band material placed around the base of the plant can capture some adults who may be entering the canopy to feed. This can be done on plants where leaf notching is observed. This technique catches the adults as they crawl to the canopy of the host, because the beetles cannot fly. Do not apply sticky material directly to host plant bark. Bands may need to be changed throughout the season as they lose their stickiness. 

Natural Enemies & Biological Control: 

Certain species of nematodes may be effective at managing root weevils. These may be most effective when used in containerized plants. These include Heterorhabditis spp. or Steinernema spp. weevils. Research in strawberry has shown that S. carpocapsae and Heterorhabditis marelatus was effective at managing strawberry root weevil pupae in that system. Pupae were significantly reduced versus the untreated control (Booth et al., 2002). They are best applied once soil temperatures reach 60°F, or in late June or early July. Moist soils at the time of application (and maintained this way for at least 2 weeks after application) may increase the success of using nematodes to manage strawberry root weevil populations. Avoid high temperatures at the time of application, such as early in the morning or in the evening. The efficacy of using nematodes to manage root weevils is impacted by many factors, including but not limited to: storage and handling, the weevil and/or nematode species used, the weevil developmental stage at the time of application, and site conditions - particularly soil moisture and temperature. Lack of soil moisture and low soil temperatures limit nematode success.

A carabid beetle, Pterostichus vulgaris, was observed in a study to be predaceous on larval, pupal and adult strawberry root weevils in Oregon; in that location, no other predators or parasites were observed (Cacka, 1982).

Chemical Management: 

Acephate (NL)

Acetamiprid (L)

Azadirachtin (NL)

Beauveria bassiana (NL)

Bifenthrin (NL)

Clothianidin (NL)

Cyantraniliprole (NL)

Entomopathogenic nematodes (L)

Flonicamid+cyclaniliprole (N)

Tau-fluvalinate (NL)

Gamma-cyhalothrin (L)

Isaria (paecilomyces) fumosoroseus (NL)

Lambda-cyhalothrin (L)

Malathion (L)

Metarhizium anisopliae (robertii) (NL)

Neem oil (NL)

Permethrin (L)


Root drench of container-grown nursery stock (for larvae) with labelled insecticides. Studies have shown that under laboratory conditions, a certain isolate of Beauveria bassiana (INRS-CFL) is effective at killing adult strawberry root weevils at a range of 54% to 77% (Sabbahi et al., 2008).

Active ingredients that may be applied systemically include: Acephate (injection), acetamiprid (injection), azadirachtin (injection, soil drench), clothianidin (soil drench), cyantraniliprole (soil drench soil injection), Metarhizium anisopliae (robertii) (soil drench), and neem oil (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: .