The proper application of insecticides to individual trees can protect them from attack by mountain pine beetle. Spraying trees to prevent attack is the most effective way to protect a small number of high-value trees.
Currently, there are three chemicals registered by U.S. EPA that are effective in preventing bark beetle attacks. These are carbaryl, permethrin, and bifenthrin. Several product trade names are available and you should talk with your county extension agent for the materials currently registered by EPA. Product labels for several materials can be found on this website, but these do not indicate any endorsement. Treatment with carbaryl has been found to last two seasons, while permethrin and bifenthrin effectively control mountain pine beetle for one season.
It is recommended that any spraying be done by a commercial licensed pesticide applicator. They have the equipment to properly spray trees and to provide for human and environmental safety.
Anyone applying these insecticides should do the following:
Be sure the insecticide used is labeled to protect pines from bark beetles.
Use the correct concentration and follow all label directions.
Use only insecticide that has been properly stored.
Apply from ground level, including exposed roots, to a height where the tree is less than four inches in diameter.
Agitate insecticide solutions to keep the material in suspension.
Check and buffer the water prior to adding the insecticide to be sure the pH does not exceed 7.
Spray only when wind speed is less than 10 mph, preferably in the early morning.
Not spray if rain will occur within 4 hours.
Attempt to use newly prepared insecticide solution each day.
Properly dispose of unused insecticide and clean equipment.
Not spray within 50 feet of any water body.
Avoid spraying near bee hives or when honey bees are active.
Wear appropriate personal protective equipment as identified on the pesticide label.
For more information on preventive spraying see Individual Tree Protection Using Carbaryl Insecticide for Western Conifer-Infesting Bark Beetles.
An informational sheet with common questions on spraying trees is available at Colorado State University.
Other types of insecticidal treatments have been tried to control bark beetles. Various systemic insecticides have been injected into trees by various means, including direct injection and plastic capsules, or by application to the soil for root uptake. Depending on the chemical used, these treatments have had limited to no success so far. Some newer chemicals are being tested for potential with injection systems, but the results are still uncertain. They are currently not registered by U.S. EPA and not available for use.
This website mentions pesticides. It does not endorse particular products, nor does it imply that the uses discussed have been registered. All pesticides must be registered in the United States by the appropriate State and/or Federal agencies.
General Information on the pesticides above
A number of questions and concerns about the use of pesticides are often asked. The following is an attempt to answer some of these questions. You will find some additional information using the pesticide link above and for more detailed information on the toxicological and ecological effects of these pesticides visit http://npic.orst.edu.
All three chemicals are highly toxic to honey bees when they come into direct contact with the insecticide. Mitigation measures should be followed to protect local bees. These include identifying nearby hives and notifying owners, relocating or closing any nearby hives, and spraying in the cooler part of the day or in the fall when bees are less active.
The cause of honey bee decline, or colony collapse disorder, has yet to be determined. Pesticides have been suggested as one of several stress factors that may be interacting and involved in the decline. The pesticides of most interest belong to the class neonicotinoids. These chemicals are not members of this class
Won’t these chemicals harm the environment?
Any pesticide used should be registered by the EPA and applied by an applicator certified by the Montana Department of Agriculture. All label directions and precautions should be used to minimize contact with non-target organisms. These insecticides are practically nontoxic to moderately toxic to birds and only low to moderately toxic to mammals. The application is directed at the trunks of trees with every attempt made to avoid drift. Real-world studies have found that 81-87% of the solution applied adheres to the tree, with approximately 97% of the remaining solution falling within 50 feet of the tree. None of these products are to be applied directly to water.
To see Pesticide Fact Sheets on these insecticides, visit National Pesticide Information Center
For additional information on human health risks from pesticides and definitions visit EPA Human Health Risks
For additional information on environmental risks from pesticides visit EPA Environmental Effects