PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Herbicide injection and control of the invasive Tree-of-heaven (Ailanthus altissima).

Lewis, Kevin^*,1, McCarthy, Brian¹, ¹ Ohio University, Athens, OH

ABSTRACT- The non-indigenous Ailanthus altissima (Tree-of-Heaven) is rapidly invading many eastern deciduous forests. A reliable herbicidal control method is needed to provide ecosystem managers with an effective, targeted herbicide application technique. Several herbicidal control methods have been previously tested to eradicate A. altissima but they differed in their mortality effectiveness and their ability to minimize the number of resprouts after application. The E-Z-Ject lance, an herbicide injection system that provides an environmentally safe and direct approach for removing invasive plants, was experimentally calibrated in this study with a dose-response analysis to determine the most effective herbicide and injection rate for the eradication of A. altissima. Calibration was accomplished by injecting an increasing number of herbicide capsules into three stem diameter classes, using three different herbicides (imazapyr, triclopyr, and glyphosate). Each herbicide/injection rate combination was replicated 10 times and the herbicide efficacy was determined at 10, 52, and 62 wks after treatment. Imazapyr was the most effective herbicide in controlling A. altissima. It provided 100% mortality when at least three capsules were injected into any tree up to 17.5 cm diameter and 90% mortality when one capsule was injected into medium-sized trees. Glyphosate was less effective than imazapyr, but provided 100% mortality when at least four capsules were injected into small and medium trees and 80% mortality when 6 capsules were injected into large trees. Triclopyr was purported to be the most effective herbicide on A. altissima when applied as a basal bark spray, but injection was generally ineffective on all three stem diameter classes. While triclopyr injected at a rate of 6 capsules per small tree resulted in 100% mortality, medium and large trees responded with less than 10% mortality at the highest injection rate. Contrary to previous herbicide experiments, A. altissima did not resprout with any of the herbicides, regardless of injection rate. The effectiveness of the E-Z-Ject lance coupled with the lack of resprouts makes it an important option for the control of A. altissima.

Key words: restoration, ohio