Department of Entomology
Entomological Notes

Carulaspis juniperi (Bouche)

The juniper scale, native to Europe, is now distributed throughout the United States. This key pest is known to attack junipers, Juniperus spp.; cypresses, Cupressus spp.; falsecypress, Chamaecyparis ; and incense cedar, Calocedrus decurrens . Ornamental plantings of juniper most commonly infested include eastern redcedar, J. virginiana ; Irish juniper, J. hibernica ; Savin juniper, J. sabina ; and Chinese juniper, J. chinensis ‘Pfitzeriana’. This armored scale insect occasionally becomes a problem in landscapes and nurseries.

Description

Eggs hatch into yellow first instar nymphs called crawlers. The female’s waxy cover is parchmentlike, white with a circular, slightly convex, yellow center that is about 1.5 mm in diameter (Fig. 1). The white waxy cover of the male is smaller and oblong shaped. Mature males emerge as winged insects that resemble tiny wasps walking on an infested twig.

Figure 1. Close-up of female juniper scales.

Life History

This species overwinters as mature fertilized females. In spring they lay an average of 40 eggs around mid-May that hatch into crawlers in 10-14 days. Crawlers seek a new feeding site on the host plant. Females go through three growth stages prior to reaching maturity while the male goes through five. In late summer males emerge, mate with females, and then die. There is one generation each year in Pennsylvania.

Damage

The first indication of plant injury caused by this scale insect is the loss of normal lustrous color. As an infestation becomes more severe, foliage on individual branches will look chlorotic or yellow and may eventually die. Entire plants are known to die as the result of severe infestations.

Management

Apply registered insecticides according to label directions from late May through June to reduce populations of the crawler stage of this pest. Dustywing larvae and adults, predators in the insect family Coniopterygidae, feed on eggs and other life stages of this scale insect. Lady beetle larvae and adults are often associated with infestations of this armored scale. Four species of wasp parasitoids are known to attack this pest.

Warning

Pesticides are poisonous. Read and follow directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams, or ponds.

Authored by: Gregory A. Hoover, Sr. Extension Associate

January 2002

DISCLAIMER

This publication is available in alternative media on request.

Where trade names are used, no discrimination is intended and no endorsement by The Pennsylvania State University or Pennsylvania Department of Agriculture is implied.

Entomological Notes are intended to serve as a quick reference guide and should not be used as a substitute for product label information. Although every attempt is made to produce Entomological Notes that are complete, timely, and accurate, the pesticide user bears the responsibility of consulting the pesticide label and adhering to those directions.

Issued in furtherance of Cooperative Extension Works, Acts of Congress May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture and the Pennsylvania Legislature. D. Jackson, Director of Cooperative Extension, The Pennsylvania State University.

The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. It is the policy of the University to maintain an academic and work environment free of discrimination, including harassment. The Pennsylvania State University prohibits discrimination and harassment against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, gender identity, or veteran status. Discrimination or harassment against faculty, staff, or students will not be tolerated at The Pennsylvania State University. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 328 Boucke Building, University Park, PA 16802-2801; Tel 814-865-4700/V, 814-863-1150/TTY.