Learning Microinjection
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 facilities and maintenance departments can add to their bag of tricks. Startup cost is not prohibitive. Doing some jobs?EUR??,,????'??+especially in tree care?EUR??,,????'??+can require equipment running into the tens of thousands of dollars. Start-up for microinjection is 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.
?EUR??,,????'??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. The rule for Mauget treatments 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. 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. 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.
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.
Learn By Doing
The steps involved in microinjection will vary depending on the manufacturer?EUR??,,????'??+and there are several. 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.
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.
