Everyone is aware of how new technology changes our lives. Computers, digital tv, gps mapping systems, all make our lives easier. Technological developments have appeared on the arboriculture scene as well. New ropes, equipment and techniques have made caring for trees much easier, safer, and more efficient over the past two decades.
New developments have hit the Plant Health Care side of arboriculture, too. One of the more recent advances involves treating tree pests with soil treatments. In the past, treating insect pests of large trees involved spraying them from the ground. As spraying large trees has become more difficult and controversial, new treatment methods have been investigated.
Trunk injections were one of the first alternative treatment methods developed. Still an important tool, injecting plant protectants directly into a tree’s trunk minimized environmental exposure and the amount of material required. Every treatment has advantages and disadvantages. Trunk injections do wound the tree. Depending on the frequency of injection, the wounding can have a minimal or a substantial effect upon the tree. New developments have reduced the damage done by trunk injection, but cannot eliminate it. Davey uses injection technology where benefits of the procedure justify the risks.
Efficient soil injection procedures are becoming a more important tool. With this technique, plant protectants are placed in a 4 to 6 inch band right next to the trunk of the tree to be treated. The plant protectant binds to the soil particles to minimize leaching and is absorbed by the tree roots.
Depending on the plant protectant used, a single treatment can protect trees for an entire growing season. In some cases, three or four spray treatments can be replaced by a single soil treatment. No damage is done to the tree, and the procedure is quick and requires minimal equipment.
Benefits and Considerations
Soil and trunk injections provide an environmentally friendly method for treating pests. The plant protectants are contained within the tree or restricted to a small amount of treated soil at the base of the plant. This provides both adequate protection for the tree, as well as minimizing exposure to birds, wildlife and people. Because the plant protectants must be moved through the tree’s vascular system, trees with dieback, trunk injuries, or those in otherwise poor health may not respond well to treatments.
Currently, only a few tree pests can be treated in this manner. Sucking insects such as aphids, scale insect crawlers, adelgids and lace bugs can be effectively treated. Leafminers, such as birch, boxwood, and alder leafminers, and some borers such as bronze birch borer are vulnerable to soil injection. While treatment of mites and foliar diseases are limited with this technique, research continues to find new materials with the characteristics necessary for root uptake from the soil.
Deciding whether or not soil or trunk injection is the most warranted treatment approach depends on too many factors to cover here. Give your arborist a call to see if soil injections are an option for your property.
Soil and Trunk Injection Quick Facts:
- New soil and trunk injection technology has provided the arborist with new tools to treat certain pests.
- Insects such as aphids, adelgids, leaf miners, and flatheaded borers are most susceptible to treatment.
- A single soil or trunk injection may be able to replace several spray applications.
- Injections pose minimal impact to the environment.
- Not all tree pests can be managed with soil or trunk injections.
- Each situation must be evaluated separately to determine the best course of action.