Strawberry Root Weevil

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Strawberry root weevil, Otiorhynchus ovatus, is the most common home-invading weevil in Minnesota.

HOW DO I KNOW IF I HAVE STRAWBERRY ROOT WEEVILS?

  • Adult strawberry root weevils feed on plant foliage, creating notches or scallops along leaf margins. The damage often resembles feeding by several other pests, including grasshoppers. Check the strawberry plant at night, when weevils typically feed, to positively identify the insect.

  • The larval stage of the beetle does the most damage. As the pest feeds on the roots, the plant is no longer able to effectively absorb water and will begin to wilt.

  • The presence of adult weevils on a plant is an indication larvae are feeding on the roots.

  • Residents experience problems with these weevils from the end of June through August. They are attracted to moisture and are often found in sinks, bathtubs, water basins and similar places.

WHAT DO STRAWBERRY ROOT WEEVILS LOOK LIKE?

  • These weevils are about 1/4 inch long, black or dark brown with rows of pits along their back. Strawberry root weevils do not fly. Sometimes people confuse strawberry root weevils for ticks; however, they are easily distinguished, as weevils have six legs and ticks have eight.

  • The weevil is about ¼ of an inch long and dark brown in color. The abdomen is quite rounded and in when viewed in profile, the weevil’s short snout can be easily seen.

  • The larvae are C-shaped and legless as shown above.  The color is dirty white with a dark head.  They grow slowly over the summer, molting five to six times.  By late fall they will be about 5/8 inch (1.6 cm) long.

  • Adults are a brownish black ¼ inch long weevils, larvae are ¼ inch long, fat, white, and legless with light brown heads.

ARE STRAWBERRY ROOT WEEVILS DANGEROUS?

  • No. The strawberry root weevils are harmless beetles.They don’t bite or sting, eat your house or stored food, or infest your pets, or transmit diseases.

CAN MY PLANTS BE DAMAGED BY STRAWBERRY ROOT WEEVILS?

  • Larvae—white, legless, and C-shaped—feed on plant roots and crowns, stunting growth, depressing yield, and potentially killing the plants.

  • Plants they attack: Strawberries, raspberries, tree fruit, and ornamentals.

WHY ARE STRAWBERRY ROOT WEEVILS IN MY HOUSE/YARD?

  • Adult weevils are wingless and enter dwellings through loose fitting doors, windows, screens, and other small cracks and openings. They crawl everywhere through the home: bathrooms, cupboards, floors, walls and ceilings.

WHAT DO STRAWBERRY ROOT WEEVILS EAT?

  • Strawberry root weevil larvae feed on the roots of strawberries, evergreens--such as arborvitae, spruce, and Japanese yew — raspberries and other brambles, grapes and many other plants. Adults start to emerge in early summer. They feed on the edges of foliage, leaving a characteristic notched appearance.

WHAT IS THE LIFECYCLE OF STRAWBERRY ROOT WEEVILS?

  • The adults overwinter in leaf litter, emerge in late spring and feed on the leaves. They lay eggs on the crowns of plants. The larvae feed on roots.

  • Weevils emerge in the spring over a four to six week period and then feed for another four weeks or so before beginning to lay eggs. They lay several eggs each day into the soil or leaf litter.  Adults live for ninety to one hundred days and may lay up to two hundred eggs in this time. The eggs hatch in two to three weeks to larva.

  • The change from larvae to adult is pupation.  Pupation takes place in the spring when the soil warms up. The pupae are about the same size as the adult and are white.  They are soft and have the outline of the parts of the adult weevil.  Pupae are inactive and do not feed.