Study

Vegetation response to herbicide control of broom snakeweed Gutierrezia sarothrae on a blue grama Bouteloua gracilis range near Laramie, Wyoming, USA

  • Published source details Gesink R.W., Alley H.P. & Lee G.A. (1973) Vegetative response to chemical control of broom snakeweed on a blue grama range. Journal of Range Management, 26, 139-143

Summary

Broom snakeweed Gutierrezia sarothrae is a small (growing to about 50 cm), dense bushy shrub, native and widespread over much of western USA. It can be invasive, especially in over-grazed prairies and grassland ranges, and is toxic to livestock in large quantities. This study evaluated vegetation response to various herbicidecontrol trials of broom snakeweed on blue gramma Bouteloua gracilis range near Laramie, Wyoming, northwest USA.

The study area had been heavily sheep grazed and in 1966 supported dense stands of snakeweed with occasional plains pricklypear Opuntia polyacantha. Blue grama comprised most of the perennial grass cover. Herbicides in water were applied (25 gal/acre) on 26 June 1966, on unreplicated, 43 x 200 ft (13.11 x 60.96 m) plots by truck-mounted sprayer:
 
1). Untreated (control);
2). Silvex 2 lb/acre;
3). Silvex 4 lb/acre;
4). Picloram 0.5 lb/acre;
5). Picloram 1 lb/acre;
6). Picloram at 0.25 lb/acre + 2,4-D at l lb/acre;
7). Picloram at 0.5 lb/acre + 2,4-D at 2 lb/acre.
 
 
Vegetation response was recorded by visual evaluations each year (1967-71). In 1971, vegetation was surveyed along 10 randomly located 30 ft (9.14 m) transects in each plot (line intercept method). To assess yield, herbage was clipped by species in 15 randomly located circular (76 cm diameter) plots in each main plot; samples were dried and weighed.

All four picloram treatments effectively controlled snakeweed (95-100% control for 3 years after application; 80-95% in year 5). Picloram also killed pricklypear.

Silvex failed totally in killing broomwood and was partly effective against Opuntia (at 2 lb/acre 25% control year 1 and 20% year 3; at 4 lb/acre 80% control year 1 and 65% year 3).
 
Blue grama (and some other grasses) was initially ‘injured’ by 0.5 and 1 lb/acre picloram rates but recovered after two years. Needle-and-thread Hesperostipa comata was damaged at the 1 lb/acre rate.
 
Subsequent recovery in combination with broomweed control resulted in range improvement 5 years after treatment. Blue gama cover increased relative to the control (control 3.8%; silvex treatments 1.5.- 2.2%; picloram treatments 7-14%) and dry yield (1b/acre) was significantly higher in picloram treated plots (control 105 lb/acre; silvex treatments 140-150 lb/acre; picloram treatments 350-680 lb/acre; note: approximate values read of figures in original paper).
 
 
Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: https://www.uair.arizona.edu/holdings/journal/issue?r=http://jrm.library.arizona.edu/Volume26/Number2/

 

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 17

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust