Treating Diseases Through Implantation and Injection

 

Adapted from Landscape Maintenance Pest Control, First Edition, University of California Statewide Integrated Pest Management Program Agricultural and Natural Resources

Here a national park employee is soil drenching with imacloprid around the base of an eastern hemlock.

One of the biggest advantages to tree injection or implantation is that there is little chance that drift or other possible public hazards will result from the pesticides applied. Here are some examples of how tree care specialists are using new technologies to treat arbor diseases.

Soil Drenches and Soil Injection

Soil drenches and soil injection are effective ways to apply certain systemic pesticides to small numbers of trees or shrubs. These application methods are especially useful in populated areas because they reduce the risk of exposure to people and eliminate the possibility of drift. Drenches and soil injection can also be used in some interiorscape settings. For applications to trees growing along city streets and in highly populated areas, soil injection or soil drenches may provide a safe and practical alternative to foliar sprays.

Hand-held equipment is practical if you are treating a limited number of trees or shrubs.

Here, a pesticide is injected into the sapwood of a tree by using a syringe-like injector. Tree implantation and injection systems supply nutrients and apply systemic fungicides and insecticides. Injection or implantation can also be used to place herbicides into the vascular system of an undesirable tree or shrub that you wish to eliminate from the landscape.

Macroinjection and Microinjection

With macroinjection, a pesticide mixture is placed into a container on the injection applicator. Small holes bored into the tree trunk provide access to the outer layers of sapwood. Tubing is inserted into the holes and connected to a manifold on the container that holds the pesticide mixture. The application device forces pesticide into the living tissue (xylem) under the bark where it is absorbed.

Pesticide delivery depends on the negative pressure in the xylem that occurs when trees transpire and lose water. Transpiration creates the negative pressure that pulls xylem fluids upwards through the tree. Microinjection will not work on dormant trees since there is no movement of xylem fluids.

Implantation

Implantation usually involves the insertion of solid chemicals contained in a water-soluble capsule, into holes that are drilled into the tree?EUR??,,????'???s outer sapwood. This method only allows for small amounts of chemicals to be applied, and only works with pesticides that will dissolve in the plant sap. One advantage to this technique is that the chemical usually is dissolved and distributed slowly over time, providing long-term pest control.