Submitted to: Proceedings of Northeastern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 11/30/2009
Publication Date: 1/4/2010
Citation: Ditommaso, A., Bittner, T., Milbrath, L.R. 2010. Management of pale swallow-wort (Vincetoxicum rossicum) using mowing and herbicides in two contrasting habitats. Proceedings of Northeastern Weed Science Society. p. 32. Interpretive Summary:
Technical Abstract: Pale swallow-wort [PSW] (Vincetoxicum rossicum (Kleopow) Barbar.) is an invasive non-native vine that is increasing in prevalence in many natural and semi-natural areas of the northeastern U.S. and southeastern Canada. This herbaceous perennial thrives in old fields and ecotones but can also establish in shaded forest understories. Effective control of PSW has been difficult and limited information is available on the efficacy of herbicides for its control in both old field and forest understory habitats. We conducted a two-year (2008-2009) herbicide and clipping study in an old field (OF) and adjacent forest understory (FU) site near Ithaca, NY. We compared the effects of seven treatments during two growing seasons on stem density and percent cover of PSW in these two habitats. Treatment plots measured 4 by 4 m and vegetation in all plots was mowed to a height of 5 cm in mid-June of both years. There were seven replicate plots for each treatment resulting in a total of 49 plots in each habitat. The seven treatments were: (1) glyphosate (Roundup Pro®) at 4.87 and 2.44 kg ai/ha in OF and FU, respectively; (2) triclopyr triethylamine salt (Brush-B-Gone®) at 0.93 and 0.46 kg ai/ha in OF and FU, respectively; (3) triclopyr triethylamine salt (Garlon® 3A) at 4.87 and 1.70 kg ai/ha in OF and FU, respectively; (4) triclopyr butoxyethyl ester (Garlon® 4 Ultra) at 2.99 and 0.43 kg ai/ha in OF and FU, respectively; (5) triclopyr butoxyethyl ester (Garlon® 4 Ultra) at 4.87 and 2.27 kg ai/ha in OF and FU, respectively; (6) an untreated check; and (7) a second mowing at the time of herbicide application. Pre-treatment assessments of PSW stem number and percent cover, in a 1 by 1m sub-plot, were made a few days prior to mowing (mid-June). The herbicides were applied in late August using a CO2 back-pack sprayer pressurized at 100 kPa. Post-treatment measurements for 2008 applications were made in mid-June 2009 and for the 2009 applications will be recorded in mid-June 2010. Thus, data (percent cover) resulting from only the first year of treatments (2008) are presented. By mid-June 2009, treatment effects differed in the two habitats. In the old field, the highest reductions in PSW cover relative to pre-treatment levels were observed for the glyphosate (46%) and triclopyr butoxyethyl (41%) (Garlon® 4 Ultra - 4.87 kg/ha)-treated plots. Plots treated with triclopyr butoxyethyl at 2.99 kg/ha resulted in only a 9% reduction. Cover of PSW in triclopyr amine (Brush-B-Gone®)-treated plots at 0.93 kg/ha increased by 17%. Mowing plots twice in 2008 resulted in a 281% increase in PSW cover. In the forest understory, PSW cover was reduced in all treatments including plots mowed twice (16%). The highest reductions in cover (56%) were achieved in the glyphosate and triclopyr butoxyethyl (0.43 kg/ha)-treated plots. The lowest reductions in cover (30%) were observed for plots sprayed with triclopyr butoxyethyl at 2.27 kg/ha. Data collected in June 2010 sampling will confirm whether the effects observed following control during this single season will be maintained. However, it is likely that observed differences in the efficacy of treatments between the old field and forest understory habitats will not change. If so, these findings suggest that management of PSW using herbicides and mowing may vary depending on the habitat being managed. Land managers should be aware of these possible differences in efficacy to ensure successful control of this invasive vine.