Healthy Choice.(controlling Asian Longhorned Beetle)
Arbor Age September 1, 2001 | Tattar, Terry A.
Microinjection Helps Fight Asian Longhorned Beetle PEST AND DISEASE CONTROL ON URBAN SHADE TREES HAS ALWAYS BEEN difficult, but dealing with the accidental introduction of the Asian longhorned beetle (ALHB) from China, in both New York City and Chicago presented a real challenge.
It was an exotic tree-killing insect that posed a serious threat to both shade and forest trees of the United States, and it had just escaped in two of the most populous regions of the country. Government officials responded quickly by destroying thousands of infested and suspect shade trees in New York City and Chicago, but another strategy to eradicate and contain the Asian long-horned beetle clearly was needed. go to website asian longhorned beetle
An extensive research program involving scientists from universities and government agencies, such as the Animal and Plant Health Service (APHIS) and the USDA Forest Service, was initiated. The results of these studies indicated that microinjection of systemic insecticides should be part of the ALHB eradication program.
The APHIS-sponsored microinjection program was launched two years ago in Chicago and was expanded this year to include the New York City area. In 2001, a total of over 40,000 trees were injected with the systemic insecticide Imicide [R]* in microinjection capsules. Although the war against the ALHB is far from over, microinjection is suddenly in the national spotlight.
Microinjection is a type of trunk injection in which small amounts – approximately 0.1 ounce – of therapeutic chemicals, contained in sealed capsules, are introduced into pre-drilled shallow injection sites around the base of a tree. Within a few hours after injection, the chemicals are distributed systemically to branches, leaves and roots by sap movement within the tree.
Although the first reports of the introduction of materials into trees date to the 12th Century it is a technology that is often misunderstood. 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 outside the tree. Under this condition of negative pressure, liquids introduced into healthy xylem through a fresh injection site will be taken into the xylem and distributed within the tree in the sap stream. It has been suggested that because the xylem of the tree accepts the liquids based on its porosity, the term infusion is more appropriate than injection when describing the movement of systemic liquids into trees.
There is no need for the use of high pressures to attempt to “force” liquids into a tree. High-pressure injection often damages tree tissues and does not place most of the injected materials into the outer xylem in which most systemic transport occurs. Low pressures sufficient to empty the injection reservoir are most effective for transport and cause the least impact on the tree. website asian longhorned beetle
A breakthrough in injection technology occurred in the 1960s when the systemic insecticide Bidrin, in microinjection capsules, was injected into trees and shown to control a variety of chewing and sucking insect pests. It was then clear that large volumes of materials did not need to be injected into a tree to control a tree health problem. Research on Bidrin demonstrated that a small volume of a concentrated systemic chemical in a microinjection capsule could provide effective tree health care.
Since that time, the focus of microinjection research has been on developing systemic formulations of antibiotics, insecticides and fungicides that were effective in low volumes. Considerable research has gone into studies of the most effective injection techniques to maximize uptake and distribution and to minimize any effects of any pre-drilled shallow injection sites. Combinations of an insecticide and a fungicide in a single capsule have recently been developed to allow microinjection treatment of both insect and disease problems with a single injection.
Microinjection is both an evolving, research-based technology and a clinical tool for the tree health care practitioner. Research on microinjection is continuing at major research universities and at government research facilities. A key goal for the future of microinjection is to determine the potential systemic uses for new tree health care chemicals which are being produced and registered each year.
Alternative to Sprays and Soil Injection Microinjection allows the introduction of systemic chemicals-such as antibiotics, fungicides, insecticides and mineral nutrients-directly into a tree without any contact with the environment. Microinjection, together with macroinjection and implants are the most commonly used methods to introduce systemic chemicals directly into the vascular system of trees. Trunk injections implants are efficient delivery systems that can be performed under most weather conditions. Systemic materials placed into the tree are rapidly available within the tree and there is no environmental contact with pesticides.
Application of sprays to shade trees in urban areas requires specialized, expensive equipment and has a negative public image. For example, if a hospital, nursing home, school, pond, stream or river is nearby or your clients and/or their abutters have pets, wildlife concerns or chemical sensitivities, spray application may not be a tree health care option.
Soil injection of systemic chemicals may represent another option but increasing concerns about groundwater contamination have limited the use soil injections in many areas.
Train to Use Microinjection Like any technology, these techniques can only be effective if applied by trained applicators who have correctly diagnosed a tree health problem. Companies that sell injection and implant products usually provide some type of training prior to use of their products. The J. J. Mauget Company, for example, requires a one-day training program before sale of any of its products. In addition, these techniques have to be applied in strict adherence to the guidelines of the manufacturers. An incorrect diagnosis will likely result in the use of an ineffective material. Improper application can be harmful to the tree.
Dr. Terry A Tattar is professor, Shade Tree Laboratory, Department of Microbiology, University of Massachusetts, Amherst, Mass. He has conducted extensive research on vascular transport and vascular diseases of trees and often presents seminars on microinjection technology.
Tattar, Terry A.
