Otiorhynchus ovatus

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 prevalant 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.