Montana State University

Southern Agricultural Research Center

"Serving the Land Grant Mission in South Central Montana"

Research Centers

Crop -- Plant Back Restrictions -- Weed ID

The correct choice of a herbicide is dependent on at least three things: The current crop, the next crop (and timeline), and the weeds you are targeting. Use this form to enter your field information. A list of herbicides registered in Montana for the conditions you specify will be generated. Current labels can be found by clicking on the herbicide name or at the Crop Data Management Systems website. Be sure to check the label that comes with your purchased product before making an application.

The intent of this web-tool is not to rank or recommend any particular herbicide, but to reduce the number of choices availiable by filtering out those chemicals that do not fit your crop, crop rotation interval, and weed spectrum.

Start the selection process by choosing the intial conditions of crop, rotation interval to the next crop and at least one weed. Click on "Build the Table" to generate a results table. You can add additional weeds directly from the page with the results table. This tool will suggest certain combinations or tank mixes, but be sure to check the labels before proceeding. We are not making a herbicide recommendation, but are helping you find the best solution for weed control in your cropping system.

'Post' indicates herbicide will be applied after the targetted weed has emerged. Typically this means the herbicide is absorbed through the plant foliage.

'Pre' indicates the herbicide will be applied prior to weed emergence and may also mean application needs to occur prior to crop emergence or even crop planting. Typically soil applied herbicides have some residual activity. Check the label for the specific timing required for the herbicide application.


Prices are an estimate of cost of product per acre and should be used for relative comparisons between products. These prices are compiled from published information from North Dakota State University (NDSU) and the University of Nebraska (UNL). Prices vary across regions, and are dictated by local economic factors. Use these prices as guidelines in your decisions for weed control.

Links to Weed Identification Websites and Apps

Return to the form

First time here? READ THIS!!!

Make Your Selections

Step 1. Choose your initial conditions:

Current CropNext Cropto be planted in:Herbicide to be applied

Step 2. Select all the weeds you need to control

barley, foxtail
barley, volunteer
bedstraw, catchweed
bindweed, field
bluegrass, annual
bluegrass, bulbous
brome, downy
brome, Japanese
buckwheat, wild
bursage, annual
canarygrass, littleseed
canola, volunteer
carrot, wild
chamomile, false
chamomile, mayweed
chickweed, common
chickweed, mouseear
clovers, annual
cocklebur, common
corn, volunteer
crabgrass, large
cress, hoary
daisy, oxeye
darnel, Persian
dock, curly
dogbane, hemp
falseflax, smallseed
filaree, redstem
foxtail, green
foxtail, yellow
garlic, wild
goatgrass, jointed
groundsel, common
knapweed, Russian
knotweed, prostrate
lambsquarters, common
lentil, volunteer
lettuce, prickly
mallow, common
mallow, Venice
milkweed, common
millet, wild-proso
morningglory, annual
mustard, black
mustard, blue
mustard, tumble
mustard, wild
nightshade, American black
nightshade, black
nightshade, cutleaf
nightshade, hairy
nightshade, silverleaf
oat, volunteer
oat, wild
onion, wild
peas, volunteer
pennycress, field
pigweed, redroot
plantain, buckhorn
purslane, common
ragweed, common
rye, cereal
ryegrass, annual
salsify, meadow
signalgrass, broadleaf
smartweed, Pennsylvania
sorrel, red
sowthistle, annual
sowthistle, perennial
sowthistle, spiny
spurge, leafy
starthistle, yellow
sunflower, common
tansymustard, western
thistle, Canada
toadflax, yellow
waterhemlock, western
wheat, volunteer

Step 3.

Reset all selections