Insect and disease organisms are identified by inspection of the entire tree for signs or symptoms of the problem. A sign is actual evidence of the organism such as the insect itself, diagnostic feeding or decay patterns, or fungal tissue (mycelia or fruiting bodies: conks or mushrooms); a symptom is the characteristic reaction of the tree to the pest or disease, such as branch die back, slow growth, or excessive resin or sap flow.  To diagnose the problem the root crown might be exposed, the tree might be climbed, and roots. leaves, or branches might be sampled. Samples are examined in house as well as  sent to the Oregon State University Plant Clinic for identification and control recommendations.


If damage to the tree surpasses the economic damage level, treatment may be recommended. Economic damage level is that amount of damage that is deemed unacceptable by the client, because the tree can no longer provide the expected benefits in its condition. The tree might be removed or treated. Treatment usually includes a combination of cultural and direct control measures. Cultural measures might include assessing soil and water conditions and making changes; adding organic mulch or fertilizer; adding beneficial bacteria and fungi to the soil, and thinning the crown to change its microclimate to decrease disease. Direct control might include pruning out damaged portions that may harbor injurious insects or disease, and treatment with chemicals that increase tree resistance or kill the insect or disease organism.

Systemic treatment to control bark beetles might include removing the infested portion and spraying the top with insecticide in the remaining top, because the California Five Spined Ips bark beetle begins attack in the top.

Large Pine with Ips         Marking  Infestation         Close-up of Attacks        Infested Top Removed  Galleries and  Beetles       Spraying Insecticide

2012-09-01 09.44.182012-08-30 19.54.382012-08-30 19.45.372012-09-01 17.55.592012-09-02 13.00.372012-09-04 09.54.00

Preventative treatment may also be by injection at the base with insecticide and fungicide via the ArborJet system. This is best done before bark beetle flights in the spring and summer, because it may take a month or more for sufficient concentrations to infuse the tree and provide protection.

Ips bark beetles               ArborJet system                 Close-up of Injectors       Black Pineleaf Scale         Weak crown with scale   Tree being injected

006 Injection Using ArborJet for Bark Beetle Control ArborJet Injection Heads 005 003 252

The blue-stain fungus carried by bark beetles is controlled in the same operation, because treating the tree with insecticide alone will not prevent damage by the fungus. Multiple species of bark beetles and their associated fungi can be controlled with the same combination of insecticide and fungicide; other agents that cause branch die-back such as branch canker fungi or shoot moth can be controlled with the same product. Black pineleaf scale, which weakens the tree and increases susceptibility to bark beetles can be controlled with additional injected systemic products. Injection can be done in evergreen conifers at any time temperature is moderate (40s or higher), especially in sunny weather.

Link to Insect Pests and Diseases