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CYPRESS WEEVIL

Stephen Bambara, Extension Entomologist

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

CYPRESS WEEVIL, Eudociminus mannerheimii Curculionidae, COLEOPTERA

General Information

cypress weevilThis weevil was first described in 1836. It was next mentioned as the cypress weevil, Eudociminus mannerheimii, in 1904 by A. D. Hopkins who wrote that the adults kill the twigs of bald cypress (Taxodium) by feeding on them. The grubs bore under the bark and cause defects in the wood as the trees callous over the injury. The cypress weevil breeds readily in scarred and fallen cypress. In 1916, its known range extended from Louisiana to New York. Since New York is outside the range of bald cypress, the cypress weevil must have an alternative host (perhaps Atlantic white cedar). Except for lists in catalogs, we cannot find any publication on the cypress weevil since 1916. Until 1998, the only previous Eudociminus specimens in the North Carolina State University Insect Collection were two collected on September 1928 from Phelps Lake and two from White Lake collected on March 14, 1953. These were all associated with bald cypress. In the Spring of 2004, we received specimens from Winston-Salem and the surrounding Triad area in Leyland cypress (X Cupressocyparis leylandii). With the abundance of Leyland cypress in the landscape the last three decades, one should keep a watch out for future infestations.

Biology

Overwintered Cypress weevil adults become active around mid-March in most locations in North Carolina. Since the 1970s, the cypress weevil, has infrequently been found damaging cryptomeria in commercial nurseries and landscapes in North Carolina. It is not certain whether the attacks on cryptomeria are occasional outbreaks or if Eudociminus will have a major impact on cryptomeria in the landscape. The cypress weevil is in the same group of weevils as the pales weevil, Hylobius pales, so it may have a similar life history. According to Insects of Eastern Forests, pales weevils overwinter as adults that may be active all winter (but in reproductive diapause) as adults in the forest litter or as larvae. This more or less agrees with what we have seen so far -- grubs are in the wood during the winter but some adults emerge almost immediately when the temperature warms. Adults feed on the stems where the bark is still green but not in the needles. Larvae were reported to feed in the wood around the crown or base of the Leyland cypress.

Control

Determine if the infestation is treatable and worth the time and money. Since the adults feed on the bark, spraying the bark with a pyrethroid such as Astro, may protect against adult feeding and to kill them as they feed on the pesticide residue. Astro is labeled for borers in the landscape, and has a good residual life. For commercial nursery (since Astro is not labelled for nursery) Onyx (binfenthrin) or another permethrin product such as Permethrin Pro, Ambush 25W or Pounce (field grown) may be needed. Though yet untested by us, Safari (dinotefuran) is labeled and would be expected to work. Acelepryn (chlorantraniliprolez) is a systemic with good activity against weevils and is labeled for soil drench on trees in the landscape. For cypress weevil control, it would be good to prune and destroy any dead wood, cull and destroy any plants that are beyond help, and then consider spraying the shrubs to prevent further feeding. It is assumed that the shrubs should be sprayed in March, early to mid-May and again in late June to early July. These dates are vague and will depend on which region of the state the infestation occurs.

Additional Information

Cypress Weevil Circular, Ent. 415, Florida Dept of Agriculture (PDF).

Other Resources

For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service.

Published by North Carolina Cooperative Extension Service

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
© 2004 NC Cooperative Extension Service

Prepared by: S. Bambara with additional information by James R. Baker, Extension Entomologist. Images by J.R. Baker.
ENT/ort-132 March, 2004

Web page last reviewed January, 2011 by the webperson.