Cedar Bark Beetle by Brytten Steed US Forest Service Phloeosinus Spp

Forest Health Protection and State Forestry Organizations March 2004

4.13 Management Guide for WEB July 2010 Cedar Bark Beetle By Brytten Steed US Forest Service Phloeosinus spp.

Beetles in this genus are native Hosts: and are primarily found on Rocky  Rocky Mountain Mountain and Utah junipers. and Utah junipers. Topics

Damage 1 Damage Life History 1 An initial yellow-green, then red- diameter are attacked, so risk to Identification 2 brown discoloration of sections of seedlings and small junipers is Management 2 the tree crown (flagging) or the minimal.. entire crown from adults feeding on They are typically non- Other Reading 2-3 twigs. The weakened twigs often aggressive, feeding under the bark of Field Guide break, producing noticeable foliage- the bole and branches of stressed, drop on the ground. Although this dying, or felled trees, or broken Management Guide Index foliage damage may not impact a branches. However, under prolonged tree’s overall heath, it does indicate stress conditions such as drought, that adult beetles are present and intense vegetation competition or active. Significant host damage or livestock damage, beetle populations death results when adults attack live may build and attack otherwise Key Points but stressed trees to produce brood. healthy trees.  Most of the 25 Typically, stems down to ¾” inch species of Phloeosinus Life History found north of Mexico are in Larvae overwinter under the the West. bark. From spring through late  They are summer, newly-emerged adults feed typically non- on the ends of branches of healthy aggressive, host trees to complete their feeding under development. After mating, adults the bark of the attack and bore into a susceptible bole and h o s t , c r e a t i n g a s h o r t , branches of longitudinal gallery where eggs are stressed, uniformly deposited along the sides. dying, or After larvae hatch out, they mine felled trees, or perpendicular to the gallery, broken severing the tree’s conducting tissue. branches. One to one-half generations may be produced each year . Egg and larval galleries. Photo by William Ciesla Page 2 Back to menu Cedar Bark Beetle Management 4.13 Identification

Discolored sections of foliage Bark removal will reveal larval (yellow-green to red-brown) on the galleries, with possible larvae, tree and/or ground are caused by pupae, and adult life stages. feeding of newly emerged adults. Numerous shot-like exit holes Small entry holes on the bole and found on boles and branches of There are no fine boring dust in bark crevices, dead, red-foliaged trees. known available webbing, and around the base of the systemic bole. insecticides.

Management Considerations

There are neither existing direct chemical controls nor silvicultural options for cedar bark beetle management at a forest landscape level.  Trees in high-value areas may be culturally managed by reducing vegetative competition, and avoiding; soil compaction, root disturbance, chemical exposure, and animal damage.  The prompt removal and treatment (burn, chip, or bury) of infested trees may help in limiting population growth.  High-value trees may be chemically treated with carbaryl (trade name Sevin) as a preventive mechanism. Trees are no longer considered chemically treatable if beetle populations are established under the bark (there are no known available systemic insecticides).