Learning the Microinjection Biz

By Erik Skindrud, regional editor

Jesus Rodriguez can carry everything he needs to microinject trees for disease, pests or fertilizer treatments. He holds a box of 24 injection capsules, a box of feeder tubes, a pliers to attach feeder tubes to capsules and a portable drill with an 11/24-inch bit to create holes in tree trunks.

Microinjection is an effective, easy-to-learn technology that small and medium-sized firms can add to their line of services. The difference is cost. Doing some jobs?EUR??,,????'??+especially in tree care?EUR??,,????'??+can require equipment running into the tens of thousands of dollars. The start-up costs for microinjection are minimal?EUR??,,????'??+in many cases just the cost of the treatment capsules?EUR??,,????'??+the small, chemical-bearing canisters that are tapped into a tree?EUR??,,????'???s trunk. Most of the tools required are already sitting in your tool box. It?EUR??,,????'???s very easy to learn,?EUR??,,????'?? said Robert Ryan of RPW Services Inc. in Fullerton, Calif. ?EUR??,,????'??You get the hang of it after a few trees. Then, with a few more applications you learn a few tricks and your speed and efficiency pick up.?EUR??,,????'??

In addition to microinjection, RPW also takes care of weed and rodent control for a large number of Southern California cities, homeowners associations and educational facilities. The simplicity of microinjection means that despite the thousands of trees the company treats each year, RPW makes do with a staff of less than 20.

A tape measure is used to measure the tree?EUR??,,????'???s circumference at chest height. One rule for treatment is one capsule for every six inches. As seen here, this 36-inch tree will receive six capsules in six freshly-drilled holes.

Job Profile

A recent job completed in Irvine, Calif. highlights some of the numbers and dollar amounts involved in a microinjection job. A homeowner?EUR??,,????'???s association hired RPW to treat close to 400 red gum eucalyptus trees for the lerp psyllid (Glycaspis brimblecombei), an insect that has decimated the trees in Southern California.

Workers experienced with microinjection develop shortcuts that help expedite their jobs. This worker, for example, has determined that the distance between the drill?EUR??,,????'???s spinning hub base and the end of the drill bit equals six inches?EUR??,,????'??+a convenient way to measure the space between capsules on the trunk.

The cost can vary by distributor, but the following figures give a good idea of what it costs to treat a tree and the amount of profit involved per tree.

The per-case cost of the insecticide capsules depends on the distributor and the number of cases purchased. With their high volume, RPW gets a lower price on the chemical than a small-volume purchaser might. The Imicide (imidacloprid) insecticide used to treat the eucalyptus trees costs up to $27 per individual tree. The contractor charges a fee of up to $15 per capsule for each treatment?EUR??,,????'??+with six capsules per tree the contracting party can end up paying close to $90 to treat a tree. So, even with labor and other costs, a company can reap a significant per-tree profit. A crew of six completed the 400-tree Irvine job in two days. The workers used close to 1,400 capsules on the job. A more precise idea about microinjection chemical price rates can be found on distributor web sites.

It is important that the holes are drilled to the proper depth in the tree?EUR??,,????'???s conductive xylem tissue. The proper depth is between 3/8 to 1/2 inch. If set too deeply, flow may be restricted by heartwood; if set too shallow, leakage may occur.

Learn By Doing

The steps involved in microinjection will vary depending on the manufacturer-?EUR??,,????'??+and there are several.

?EUR??,,????'??You get the hang of it after a few trees. Then, with a few more applications you learn a few tricks and your speed and efficiency pick up.?EUR??,,????'???EUR??,,????'??+Robert Ryan, RPW Services Inc.

The J.J. Mauget Co. pioneered the use of small capsules that are tapped into a trunk. Florida-based Tree Tech offers a similar system, although the formulas in its capsules differ. ArborSystems?EUR??,,????'??? method employs a reusable hypodermic needle.

Once placed in the tree, the technician squeezes the capsule until the top is compressed to its pushed-in position. The action pressurizes the capsule, pushing the active ingredients into the tree.

Each company offers training and technical support for its products. All the methods are quick and easy compared to other pesticide application methods, but operators need to remember that handling any potent chemical requires careful label reading and following of directions. Federal EPA regulations call for technicians to wear safety glasses, long sleeves, boots and rubber gloves when working with the chemicals. (Rules vary depending on the chemical used?EUR??,,????'??+safety guidelines are provided with each product.) Some of the chemicals are more toxic than others?EUR??,,????'??+and some pose special risks to amphibians and other aquatic creatures. It always pays to read the label?EUR??,,????'??+and follow the rules. The photos that accompany this article give a step-by-step look at the microinjection process. The average time spent per tree is under five minutes.

The active ingredients are usually taken up into the tree within a few minutes. The time will be even shorter in hot weather because water flow in the tree is speeded up. Crewmembers are usually ready to remove capsules by the time they have treated the last tree on a site.

Contact information for microinjection system manufacturers can be found in the advertiser index under ?EUR??,,????'??Plant Accessories.?EUR??,,????'??