Submitted to: Western Society of Weed Science Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/18/2007
Publication Date: 3/13/2007
Citation: Seefeldt, S.S., Conn, J.S., Jackson, B., Sparrow, S. 2007. Control of Bird Vetch in Alaska. Western Society of Weed Science Meeting Proceedings. Interpretive Summary: Bird vetch is a climbing weedy plant that came to North America from Europe. Bird vetch can invade areas with few soil nutrients and that have not been disturbed, which is quite different from many non-native invasive plant species. Bird vetch is expanding along Alaska roadsides, in urbanized areas, and in low density aspen and spruce stands. A greenhouse study was conducted to determine which of six herbicides were most effective at controlling this plant species. A field study to determine whether the three most promising herbicides from the greenhouse study was conducted in the summer. For each herbicide, three herbicide rates were tested. Two application times were tested, just after the plant starts growing in late June and just before the plant starts flowering in late July. Only one herbicide, clopyralid, proved to be acceptable for control of bird vetch, killing over 95% of the plants at the early application date. No herbicide worked well at the late application date. The results of this research will be used to develop methods for controlling bird vetch in Alaska.
Technical Abstract: Bird vetch is a perennial Eurasian plant which, unlike many exotic weed species, can invade low fertility areas that have not been disturbed. It also is found in pastures, woodland, and tall forb communities. Bird vetch is expanding along Alaska roadsides, in urbanized areas, and in low density aspen and spruce stands. A replicated greenhouse study was conducted in 2005 and again in 2006 to determine efficacy of six herbicides for bird vetch seedling control. Bird vetch seedlings were tolerant of reduced rates of chlorsulfuron, and 2,4-DB; however, they were completely controlled with clopyralid, dicamba plus diflufenzopyr, triclopyr, and 2,4-D at a 1/4 to an 1/8 of the full label rate. These results were used to develop a replicated field study in the summer of 2006. Clopyralid, triclopyr, and 2,4-D were applied at three rates (1, ½ and ¼ of the full label rate) and applied at two times in the growing season, when bird vetch was in early vegetative growth (June 30) and just before bird vetch flowering (July 24). All three herbicides were more effective when applied earlier compared to later, however only clopyralid provided acceptable control (>95%) when applied early at 105 and 53 g ai/ha. The results of this research will be used to develop methods for controlling bird vetch in Alaska.