Questions answered by the Digital Arborist!
Micro Injection and Insect Control

Insects play a major role in Mother Nature's grand scheme of things. Every where you go
there are insects: at the office, at home and outside. Trees are no exception.

The number of species of insects that make their home in trees is uncountable. But not all
insects are detrimental. Ladybugs, for example, eat other insects. These are considered beneficial
insects. However, if your tree catches the wrong bug it could mean certain death. Detrimental insects
are those that feed off and/or lay eggs in the tree for example, Webworms. Although not all bad insects are fatal, they can cause a beautiful shade tree to become disfigured.

There are three basic types of insects: chewing, sucking and boring. The first two usually only
cause aesthetic damage. Borers, on the other hand, will lead to certain death if they are not tended
to. The part of the tree borers feed off of is the vascular tissue. If they are allowed to feed for too
long, the tree will not have enough water and sugar conducting tissue left to support itself.

Diagnosing insect problems can be a bit tricky. Often times insects are only a result of bigger
underlying problems; and often times insects will cause other problems that must be attended to. If you
think your trees have an insect problem or if you are not familiar with insect symptoms consider having
an arborist check it out. You will probably need him to apply the treatment anyway.

So how are insects treated? In the past, broadcast spraying with high-pressure equipment has
been the method of choice. There are many problems with this method. Number one, it is inefficient;
studies have shown that about 7% of the chemical sprayed is actually available to attack the insect.
Mostly due to drift, evaporation and other related problems. Second, the insecticide attacks beneficial
insects as well as detrimental ones. Third, most sprays only give a four-week residual effect. Last but
not least, broadcast spraying introduces harmful chemicals into the environment. New technology has
provided us with much better alternatives.

Micro-injections are the new way to handle many insect problems. With this method a closed
system is made between the tree and the pesticide. No harmful chemicals in the environment, and only
insects feeding on the tree are affected. The injection units are applied by drilling a small hole in the
trunk of the tree, approximately 6 in. from the ground, and inserting a tube. It works just like an IV
does on people. If trees are only treated once every several years the wounds will have plenty of time
to heal and are not a problem.

Another method is injecting high concentration, low volume insecticide directly into the soil.
The tree then absorbs the insecticide through its roots and distributes it evenly through out the tree.
Because a low volume is applied, less leaching occurs resulting in minimal environmental exposure.
One application at the beginning of spring will give season long control. Again, only insects feeding on
the tree are affected. One example of an insect best treated with soil injection is tent worms.

By Keith Brown
Certified Arborist