AN EVALUATION OF APPLICATION TIMING AND HERBICIDES TO CONTROL AILANTHUS ALTISSIMA

Open Access
Author:
Johnson, Jon Maynard
Graduate Program:
Horticulture
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • James C Sellmer, Thesis Advisor
Keywords:
  • cut stump
  • cut surface
  • basal bark
  • herbicide treatment timing
  • Ailanthus altissima
Abstract:
Ailanthus (Ailanthus altissima [Mill.] Swingle) has become naturalized across the continental United States. Along roadside right-of-ways it can be a visual hindrance and road hazard if left untreated. When mechanically cut by roadside crews this plant sprouts quickly and aggressively from the stump and root system adding to routine maintenance costs. Previous research has indicated that treating cut stumps with herbicide limits sprouting and that treatment timing may further enhance sprout control. The focus of my research was to study the control of this tree species by evaluating (1) cut stump and herbicide treatment timing, (2) a series of herbicide modes of action on cut stumps, and (3) basal bark herbicide application timing. Measurements of surviving growth including root and stump sprouts were used to determine levels of control. All timing and herbicide treatments were effective in controlling the emerging stump sprouts with cut surface treatments. Herbicide-treated stumps showed 84 to 99% stump mortality compared to 41 to 52% for cut but untreated stumps. Root sprout numbers far exceeded the number of originally cut trees for all herbicide and timing treatments. Basal bark treatment, which is much more economical to perform, provided 100 percent control of treated stems, but resulted in root sprout numbers greater than the number of originally treated trees. This work increases our understanding on the role of application timing, treatment methods, and herbicide selection on the sprouting response of Ailanthus.