Using Microinjection Technology

By Terry A. Tattar, Ph.D., Professor,
Shade Tree Laboratory, Department of Microbiology,
University of Massachusetts

Microinjection allows the introduction of insecticides, fungicides and antibiotics without any contact with the environment.

Why Is Microinjection Important?

Lawn and landscape professionals are increasingly being asked by homeowners, and condominium and apartment managers to control health problems on their trees.

Application of sprays to shade trees in urban areas, however, requires specialized, expensive equipment and has a negative public image. Microinjection allows the introduction of antibiotics, fungicides, insecticides and mineral nutrients, directly into a tree without any contact with the environment. Microinjection has become an increasingly popular alternative to spray applications in the control of health problems of urban trees.

What is Microinjection and How Does it Work?

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. The injected chemicals are then distributed systemically within the tree to the branches, leaves and even roots within a few hours after injection by sap movement.

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 injected through a fresh injection wound are distributed within the tree in the sap stream.

High-pressure injection often damages tree tissues and does not place the injected materials into the outer xylem where 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.

Materials injected into the tree during the fall will move up into the branches and down into the roots.

Fall Applications of Microinjection Treatments

In the fall as trees in temperate climates and subtropical climates go into dormancy many plant pathogens and insect pests continue to be active. Fall treatments lower pest and pathogen populations and give trees protection against health problems in the following spring. The root growth without shoot growth that occurs in the fall facilitates treatments of nutrient abnormalities. A trees vascular system remains active until the soil temperatures drop below 40 degrees F (5 degrees C). Materials injected move both upward into the branches and downward into the roots. The following 4 examples are common tree health problems that can be treated in the coming fall months by microinjection technology: leaf scorch, adelgids, anthracnose, and nutrient abnormalities.

Summary

Tree health care is an expanding area of need and opportunity for the lawn and landscape industry. A further advantage to adding microinjection to the services you provide is the low initial investment required to perform this service.

CONTRIBUTORS

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.