Study: Efficacy of Herbicides in Buckbrush Control

Buckbrush
Figure 1: Buckbrush (4-year-old plant) in pasture by Niobrara State Park in northeast Nebraska. (Photo by Stevan Knezevic)

Study: Efficacy of Herbicides in Buckbrush Control May 22, 2018

Buckbrush (Symphoricarpos orbiculatus) is a perennial weed commonly found in pastures and rangeland in northeast Nebraska (Figure 1). It often occurs in heavy stands, which can reduce desirable plant species by as much as 84%. Buckbrush also can significantly deplete soil water to the detriment of pasture grasses, particularly in dry conditions.

In 2016 and 2017 we compared the effectiveness of seven herbicides for control of buckbrush. Herbicides were sprayed in early June, when Buckbrush had 2-4 feet of green growth. The evaluated herbicides were:

  • 2,4-D LV ester® (2,4-D ester [3 qts/acre]),
  • Curtail®/Cody® (clopyralid + 2,4-D [3 pts/acre]),
  • Perspective® (aminocyclopyrachlor + chlorsulfuron [8 oz/acre]),
  • Cimmaron Plus® (metsulfuron-methyl + chlorsulfuron [0.5 oz/acre]),
  • Grazon P+D® (picloram + 2,4-D amine [4 pts/acre]),
  • Milestone® (aminopyralid + triclopyr [7 oz/acre]), and
  • Chaparral® (aminopyralid + metsulfuron-methyl [1.25 oz/acre]).

Results

Perspective® provided the best control (80-83%) of buckbrush, and the control lasted over one year (Table 1). Cimmaron plus®, 2,4-D LV ester® and Grazon P+D® provided 75-98% control, but it only lasted for one season (90 days after spray). Chaparral® and Curtail®/Cody® provided fair control (62-66%) that lasted for one season. Milestone provided poor control of buckbrush. 

These results indicated that a single application of only one herbicide provided buckbrush control for slightly more than a year. This two-year study suggests that repeated applications of Perspective®, Cimmaron plus®, 2,4-D LV ester® and Grazon P+D® are needed to achieve complete control of buckbrush. A multi-year study is needed to confirm this hypothesis.

Table 1. Herbicide Efficacy for Control of Buckbrush
HerbicideRate/Acre% CONTROL
30 DATa
% CONTROL
90 DAT
% CONTROL
371 DAT
2,4-D LV ester® 3 qts 60 98 50
Curtail®/Cody® 3 pts 50 62 40
Perspective® 8 oz 80 83 83
Cimmaron Plus® 0.5 oz 66 75 27
Grazon P+D® 4 pts 53 80 23
Milestone® 7 oz 45 40 17
Chaparral® 1.25 oz 63 66 33
a Days after treatment.