Update of Spotted Knapweed Control on Boondock Roads

Update of Spotted Knapweed Control on Boondock Roads

July 12, 2013

Spotted knapweed (Centaurea stoebe) lined Boondock roadsides. Application of two herbicides, Perspective and Milestone, occurred late spring 2012 using ATV mounted sprayers. Rebecca Durham installed ten vegetation survey plots 20ft x 3ft to document how herbicide affects native species. This update recounts the effects of the surveys.

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Spotted knapweed (Centaurea stoebe) lined Boondock roadsides. Application of two herbicides, Perspective and Milestone, occurred late spring 2012 using ATV mounted sprayers. I installed ten vegetation survey plots 20ft x 3ft to document how herbicide affects native species (Image 2). Seven plots received Milestone, two plots received Perspective, and one plot received no treatment.

Table 1. Summary of herbicide effects on native species from plot data.

Table 2. Summary of herbicide effects on native and non-native species from ocular data.

Image 2. Red lines depict a plot. Dimensions measure 3ft X 20ft.

Image 3. Although effective for knapweed control, these two herbicides prove ineffective for other problematic invasives. Leafy spurge, cheatgrass, sulfur cinquefoil, and houndstongue continue to grow along roads. Crews will spray remaining weed patches summer and fall of 2013.

Image 4. Ninebark shows no tolerance to Milestone. Elderberry, snowberry, maple and chokecherry display partial sensitivity: these shrubs responded with dead branches but the individual survived.

Image 4. Some natives tolerate Milestone and Perspective. Biscuitroot and mountain brome cover the road shoulder one year post-treatment (Lomatium ambiguum and Bromus carinatus).