Introduction Tree health care is an enlarging area of service provided by landscape professionals. Microinjection has enabled many landscape professionals to add tree health care services to the landscape management services they already provide. A wide range of tree health care products are currently available in microinjection capsules, including insecticides, fungicides, antibiotics and mineral nutrients. With tree microinjection, there is no need to invest in expensive spray equipment. A battery powered drill, a hammer and a willingness to learn the microinjection technique are all the investment needed to add tree microinjection services to your business. What is microinjection? Microinjection is a type of trunk injection where small amounts (approximately 0.1 ounce) of therapeutic chemicals, contained in sealed capsules, are introduced into shallow trunk wounds around the base of a tree. First, a small drill hole, approximately 3/16 inch (3mm) in diameter is made into the lower trunk of the tree. Second, a hollow spout, known as a ?EUR??,,??feeder tube,?EUR??,,?? is placed into the hole and an injection capsule is placed onto the end of the spout. The plastic membrane is then ruptured, usually by contact with a hammer and the systemic chemicals move from the sealed capsule, down the feeder tube and into the tree. The injected chemicals are then distributed systemically by sap movement within the tree. The rapid movement of tree sap often carries the systemic chemicals to the branches, leaves and even roots within a few hours after injection. Materials in liquids can be injected into the woody tissues, known as xylem, of trees because the pressure within the xylem is below that of atmospheric pressure on the outside of the tree. Under this condition of negative pressure, liquids introduced into healthy xylem through a fresh injection wound will be taken into the xylem and distributed within the tree in the sap stream. Microinjection capsules are used under low pressure, usually less than one atmosphere, when they are placed onto the tree. The purpose of this low pressure in the capsule is merely to aid in emptying the capsule reservoir and not to force the systemic chemical into the tree. There is no need for the use of high pressures to attempt to ?EUR??,,??force?EUR??,,?? liquids into the tree. High pressure injection can injure tree tissues, especially the bark and cambium. Low pressures sufficient to empty the injection reservoir are most effective for transport and cause the least impact on the tree. What types of tree health problems can be treated with microinjection? Many chewing and sucking insects, diseases caused by fungi and bacteria, and mineral nutrient deficiencies have been controlled by microinjection for over 30 years. In general, most tree health problems that have been treated by spray applications or soil injections can also be controlled by microinjection. A complete list of microinjection products registered for treatment of tree health problems is available from companies that produce and sell these products. How to get started in microinjection The best way to learn about microinjection is to attend a training program. These programs are held regionally around the county, usually during the late fall, winter and early spring. The J. J. Mauget Company, for example, offers a one-day training program before the sale of any of their products. In addition, home study programs are available to provide assistance in learning how to perform microinjection. Companies that sell microinjection products usually have information booths at green industry trade shows and are willing to provide some type of training prior to use of their products. Benefits for the Landscape Professional The landscape professional who maintains trees on clients?EUR??,,?? properties must be concerned with both the efficacy and cost-effectiveness of any treatments that are used. Microinjection provides the following benefits when compared with spray applications and soil injections: 1. Rapid application 2. Low start-up cost 3. Many product choices 4. Flexibility of use 5. Easy and compact storage 6. Client and applicator safety 7. Easy disposal 8. Low treatment cost Microinjection is a great tool- Use it correctly! Like any technology, microinjection is most effective if applied by trained applicators who have correctly diagnosed a tree health problem. An incorrect diagnosis will likely result in the use of an ineffective material. In addition, microinjection has to be performed in strict adherence to the guidelines of the manufacturers of microinjection products. Improper application can be harmful to the tree. Most manufacturers also offer year round advice in technical support hotlines to help applicators with any questions on how and when to use their products. For More Information: Dr. Tattar has conducted extensive research on vascular transport and vascular diseases of trees, and often presents seminars on microinjection technology. He can be reached by phone at 413-545-2402, by fax at 413-545-1578 and by email at tattar@microbio.umass.edu.