Injection of chemicals directly into the sapstream of trees has been used for over three decades.  Various techniques have been used with varying degrees of success.  The methods have been used for treating insect pests, fungal and bacterial diseases and for nutritional supplementation. 

ACECAPS AND MEDICAPS.  We do not recommend this method of treatment in any circumstance.  It involves drilling multiple 3/8 or 1/2 inch holes, leaving caps in place, for a product that has a very short residual and limited proven effectiveness.  

MACROINFUSION.  This technique involves infusing relatively large amounts of fluid containing the active ingredients diluted with water in most instances(as much as 50 gallons in very large trees).

Holes are drilled through the bark and into the xylem (active sapwood) at multiple points around the base of the tree, often into the root flares at and below ground level.  Infusion tubing is attached and the fluid is infused, in amounts up to several gallons.  The fluid gradually moves upward and diffuses outward to saturate many of the active tissues with beneficial chemicals.  This method is very effective for Dutch Elm Disease prevention, using Arbotect, a fungicide.  It has been used to control other fungal diseases, such as anthracnose and oak wilt and for nutritional deficiency such as iron deficiency chlorosis and manganese deficiency chlorosis.  

MICRO-INJECTION.  This technique uses holes punched through the bark, often somewhat higher on the tree and much less chemical.  At each injection point, from 1 to 2 milliliters of concentrated active ingredient is injected just under the bark.  We have tried this technique and have been unhappy with the results and dismayed by the technical problems we have encountered.  In some instances, we have observed bark separation and injury to the cambium (growth) layer under the bark.  In addition, the tissue levels of active ingredients is much lower, resulting in poor actual results (poor or no control of the target insect or disease).  Confirmation of this unfortunate fact is found in the multistate monograph, see pages 14 to 16, (where Imicide and Pointer showed continued decline of trees treated even every year) at: http://emeraldashborer.info/files/Multistate_EAB_Insecticide_Fact_Sheet.pdf

MICRO-INFUSION WITH THE TREE I.V. OR QUICK-JET INJECTOR.   This technique was developed by Arborjet a few years ago and found to be very effective in controlling Hemlock Woolly Adelgid in eastern states.  More recently, it has been tested extensively for treatment and prevention of Emerald Ash Borers.  Several holes are drilled, but fewer than either technique discussed above.  Arborplugs are placed and infusion needles are placed into them, after which the product is infused from the Tree IV or Quik-jet using pressure applied by a hand pump or compressed air. One important advantage of this method is that much larger quantities of treatment chemicals can be introduced.  See picture to right.

Some companies will advise that trees should not be drilled to administer chemicals and will advise other methods of application.  There are several problems with this argument:  1) Drilling is the only way to administer the very best treatment that can save infested ash trees (emamectin benzoate) and protect them for a full two years  2)  Trees infested with ash borers need life-saving treatment administered in any way possible  3)  a recently published report documents that the trees do not suffer harm after these treatments- the trees show excellent healing response, growing good healthy wood over and around the injections sites with no decay or other problems.

We have been using the Arborjet system since 2002..  We have treated thousands of ash trees and have had excellent results preventing and treating ash borers.  We have used the system for scale treatment, for fungal disease prevention and for nutritional treatments.

Since 2008 we have been using TREE-Age, active ingredient emamectin benzoate for ash borer treatment and prevention.  Emamectin benzoate has been tested by Michigan State University and found to give 99 to 100 per cent control of Emerald Ash Borer larvae and adults for at least two years with one injection.  It is also labelled for use on trees other than ash trees, notably birch trees that get the closely related bronze birch borer.  We are also using it to control the two-lined chestnut borer that is killing many oak trees.  TREE-Age is the only insecticide PROVEN effective for two years.  See findings on pages 13 to 16, in the report at: http://emeraldashborer.info/files/Multistate_EAB_Insecticide_Fact_Sheet.pdf

QUICKJET INJECTOR.  The method that we use most for infusing chemicals into trees is the Quickjet injector or the Quickjet Air injector.  This tool was developed by Arborjet and we had the privilege of doing some of the testing of the prototype.  We are using this method for almost all of our injections now.  The needle is similar to the infusion needles of the tree IV and the chemical is infused through arborplugs. See picture to left.  Unlike the micro-injection discussed above, the injection is deeper into the active sapwood, rather than into the cambium layer, and no bark separation or cambial damage is observed.

The charge for micro infusion using either the tree IV or the Quickjet varies from $5 to $15 per trunk diameter inch. The main variable in the cost is the dosage of the chemicals used.  The injected fungicides and insecticides vary in cost from $78 per quart up to $520 per pint.  The chemical for borer protection is the most expensive.