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Arthropod Pests of Leyland Cypress

Stephen Bambara, Extension Entomologist

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


- Green or brown cone-like bags 1/4" - 3"
- Defoliated areas of plants
- Infestation spreads slowly from one plant to adjacent plants in a
hedge row
- Breakage points at callous branch swellings
- Caterpillars remain enclosed within protection of bag
- Over winters as eggs within bags
- Eggs hatch May; larvae feed through July

*Hand pick bags any time of year
*B.t., Sevin, pyrethroid, Conserve June to midJuly

Spruce Spider Mite

- Browning noted during Summer or Winter
- Browning located on inner portions of branches
- Flattened oval eggs or egg shells present in Summer and Winter with center thread
- Almost black body with pale yellow-brown legs
- Streak dark olive when smeared on paper
- Eggs laid at base of needle
- Use 10X hand lens to check

*Horticultural oil, Floramite, Hexygon, sprayed in cool season while mites active. Follow-up sprays often required with oil.

Arborvitae Spider Mite

-Adults generally pale yellow-green
- General yellowing or bronzing of foliage
- Adult female overwinter in bark crevices
- Streak yellow when smeared on paper
- Crawlers appear June, eggs flattened and without stipe
-Active Spring through Fall

* Horticultural oil or other miticides, Hexygon ovicide. Repeat 14 days later.

Minute Cypress Scale

- Minute armored scale
- Circular to oval in shape and parchment-like, often with yellow in center
- Found on needles and bark
- Needles turn yellow and go to brown
- Dieback may occur
- Crawlers hatch late spring
- Overwinter as female on needles

* Horticultural oil during crawler stage
repeat treatment 14 days later


- Foamy spittle masses on twigs
- One generation per year
- Wingless nymphs in spittlemass during Spring
- Adults leave spittlemass and feed elsewhere during Summer
- Not usually heavy damage

*Wash away with water hose
*Ignore in low numbers

Cypress Weevil

- Grubs bore under bark and at root collar
- Half-inch borer exit holes and galleries most often at root collar
- Decline or death of tree
- Callous may form over injured areas
- Adults feed on tender green bark at tips
- Adults active at first break of cold weather

*Protective bole and base sprays in spring with Astro or Onyx. * Astro or Onyx foliar sprays in early spring for foliage feeding damage

Maskell Scale

- Armored scale 1.5mm, long oystershell-like
- Light brown and white
- Possible two generations
- Crawlers present early June & Aug.

* Horticultural oil during crawler stages with follow up at 14 days

maskell scale

Phloeosinus sp. Bark Beetles

- Reddish brown-black, 2-3mm long
- Mine in tips causing tip color fade, possible dieback
- Galleries in cambium under bark possibly girdling tree
- Not commonly a problem

* Avoid drought stress

Alternative Plants-

Dr. Bob Lyons, former director of the J.C. Raulston Arboretum at NCSU, suggested the following plant material as a similar alternative to Leyland Cypress.
Thuja 'Green Giant'
and cultivars of Cryptomeria japonica

Thuja and cryptomeria are susceptible to many of the same insects. No plant is perfect. To reduce overall pest problems with plant screening borders, try diversity by alternating dissimilar plant material in groups of threes or fives. Check what works best in your area. Some possibilities are ligustrum, abelia, rhododendron, wax myrtle (Myrica), magnolia and forsythia.
Al Cooke has assembled a list of evergreen screening plants for Chatham County.

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 your county North Carolina Cooperative Extension Service agent.

Other Resources

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.

Prepared by:S. B. Bambara, Extension Entomologist. Photos © J.R. Baker and S.Bambara. Permission required.
ENT/ort-133. July, 2004

Web page last reviewed January, 2011.