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TWOBANDED JAPANESE WEEVIL

James R. Baker, Extension Entomologist Emeritus

CAUTION: This information was developed for North Carolina and may not apply to other areas.

TWOBANDED JAPANESE WEEVIL, Callirhopalus bifasciatus (Roelofs), COLEOPTERA

The twobanded Japanese weevil is about 1/4 inch long. It is light or dark brown with a short, blunt snout. The wing covers (elytra) are striped with indistinct white lines in the grooves, white spots on the apical half, and a dark brown or black transverse band. The eggs are small and cream colored. They are laid in small masses and sealed inside a folded leaf. The larvae are typical weevil grubs: white, legless and with a brown head. They are about 5/16 inch long. The pupa is white with brownish hairs. They are about 1/4 inch long.

Biology

The twobanded Japanese weevil was first found in the United States in 1914 near Philadelphia. It is now established in the eastern United States. Some of the plants attacked by the twobanded Japanese weevil are ash, azalea, barberry, burr marigold, camellia, dogwood, lilac, mountain laurel, privet, rhododendron, rose, spirea, strawberry, and weigela. Twobanded Japanese weevil larvae feed on plant roots, but the adults do more serious and apparent damage. The weevils feed extensively on new leaves, shoots, and inner foliage. As a result, infested plants are tattered and unhealthy in appearance.

The twobanded Japanese weevil is parthenogenetic (no males have been found). Eggs are deposited in folds along the margins of leaf fragments or in dead leaves that have the free edge sealed to form a pod. After hatching, the larvae burrow into the ground and feed on roots. These weevils have fused wing covers and no flight wings and thus are unable to fly. They feed during the day, but if disturbed, drop to the ground readily and remain motionless. There is only one generation each year.

Control

Because twobanded Japanese weevils feed during the day but drop from infested shrubs when disturbed, many can be trapped and destroyed. Taking care not to jar the plant, place a white cloth or large sheet of paper under the shrub and then tap or shake the plant vigorously. Many weevils will fall off and can be easily collected. Destroy the weevils by dropping them into a can of water with a small amount of solvent or by freezing them or some other method.

Twobanded Japanese weevils are apparently resistant to carbaryl (Sevin), diazinon, and malathion. Two small demonstrations conducted in 1981 indicated that acephate (Orthene) at the labeled rate gave good control when applied as a foliar spray and drench. Azatin EC is specifically labeled with a full Federal registration for the twobanded Japanese weevil although this pest is not listed on the label. In addition, some labels of the following pesticides are worded to allow their use for twobanded Japanese weevil under Section 2 (ee) of the Federal Insecticide, Fungicide and Rodenticide Act.
Commercial growers and landscapers can use a pyrethroid (Astro, Mavrik, Talstar or Tempo 2) for control. Homeowners may find BioNeem and formulations of cyfluthrin or permethrin at lawn and garden centers.

Tests on the similar black vine weevil show pesticides may be applied to the media or soil surface as a drench to control black vine weevil larvae. Imidacloprid (Merit, Marathon) can be used as a soil injection or drench against larvae. Scimitar & Demand (Oregon study) and Talstar (Ohio study) are effective when adults are present. Aloft may also be an effective product.


Pesticide (Trade Name) Formulation Amount 
acephate (Orthene) 75% soluble powder 1 tablespoon per gallon for Tree and Ornamental) 1 pound per 100 gallons of water. (Not labeled for the twobanded Japanese weevil but labeled for black vine weevil, strawberry root weevil, root weevil, and numerous other pests on many ornamental plants.)
acephate (Orthene) 9.4% emulsifiable concentrate 3 tablespoons per gallon of water. (Not labeled for the twobanded Japanese weevil but labeled for black vine weevil, obscure root weevil, and numerous other pests on many ornamental plants.)
azadirachtin (Azatin EC, BioNeem) 3% emulsifiable concentrate Azatin EC is federally labeled for twobanded Japanese weevil but the pests and rates of application are not listed.

Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical. For assistance, contact an agent of the North Carolina Cooperative Extension Service in your county.

Other Resources

© 2001 NC Cooperative Extension Service
Prepared by: James R. Baker, Extension Entomologist

ENT/ort-34  August 1994 (Revised), Scientific name corrected on 08 Oct 96

Web page last reviewed January, 2011 by the webperson.