Overview
The San Bernardino forest is currently experiencing an infestation of bark beetles that are contributing to the demise of hundreds of thousands of pine trees. These beetles are always present in nature. A healthy and vigorous tree usually has the ability to pitch out attacking beetles thus preventing colonization. In a normal year the pines would be metabolizing, moving water and nutrients up the xylem and carbohydrates down the phloem. Because of the lack of moisture in the root zone due to the drought in recent years, this process has been shut down or nearly so. In fact, there are those that believe that many of the tree problems are caused as I much by the lack of water and nutrients as by the beetle itself. However, it is true that in this state of dormancy, the tree becomes totally unable to fight off an attack.
Treatment
The focus of any control program must be to return the tree to a healthy and vigorous state. Your first line of I defense is to act now and try to eliminate as many points of stress as possible.
Watering: It is extremely important to initiate a watering program that will replenish the moisture in the feeding zone. This is an area that encompasses twice the diameter of the drip zone to a depth of anywhere from 2 ft. to 15 ft. depending on the size and age of the tree as well as the soil characteristics. This watering program should replenish moisture in this zone at least once a month throughout the entire year.
Implants: Trunk implants should be used to address two issues: nutrient deficiency and insecticide placement. Because the tree is near stress induced dormancy, it is unlikely that it has the ability to uptake the adequate amount of nutrients via the root system. By using an injectable fertilizer, it is possible to bypass the stressed root system as well as avoiding any problems associated with soil chemistry. It is possible to maximize I control with the minimal amount of insecticide and eliminate concerns for over spray or spray drift.
The application ingredient is Acephate, a proven insecticide with both contact and systemic action. It has been shown to be active in pines for up to 1 year.
The implants are placed every 2 1/2 to 3 inches around the circumference of the tree in a stairstep fashion. The natural sap flow will "systemically" absorb the chemicals and distribute it throughout the tree. The active layer of cambium will soon grow over and cover the implant site.
Sanitation: Remove all dead and dying plants around the treated tree. These plants are breeding grounds and will become a source of additional infestation next spring.
Thinning: Thin unwanted vegetation around pines. This will eliminate other plants from competing for water and nutrients.
Act Now! Once a tree has been colonized in all likelihood it will die. Address every issue which could be causing stress to the plant and make every effort to eliminate the cause.