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Tall Whitetop

Herbicide

Herbicide application can be effective

Example Photo

Choose appropriate herbicides

There's currently only one herbicide registered for use in wet areas that shows some effectiveness in controlling tall whitetop: 2,4-D (water label). There are a few more choices for dry sites. The chart below gives some recommendations. For best results, follow the recommended application rates, application periods and all precautions. After the initial application, it's essential to monitor the site for several years, as reapplications or spot treatment will be needed. Revegetation of treated sites is essential. When using Chlorsulfuron and Metsulfuron, be aware that these chemicals may prevent desirable seeds from sprouting.

Chemical Name Application Rate
(based on active ingredient)
Examples of Brand Names1 Application Rate
(based on formulated brand
Application Timing and Precautions
DRY SITES (includes rangelands, roadsides, native hay meadows when seasonally dry, dry upland areas)
2, 4-D Up to 2 pounds per acre. NOTE: a maximum of 2 pounds per acre per year may be used per most label directions. Weedone 638® Weed-B-Gone® Calculate application rates based on active ingredient. Apply at bud to early bloom stage. NOTE: Use the amine form of 2, 4-D. It is cheaper and as effective as other forms. Multiple applications per year can be effective.
Chlorsulfuron 0.75 - 1.25 ounces per acre Telar® 1 - 1.5 ounces per acre Apply at bud to early bloom stage. Very toxic to broadleaf plants, such as flowers and vegetables.
Glyphosate +2, 4-D Use formulated product only Landmaster® 54 ounces per acre Apply at bud to early bloom stage. Apply formulated product only. Method has not been tested in Nevada.
Imazapyr 0.75 - 1.5 pounds per acre Arsenal® 1.5 - 3 pints/acre Apply at bud to early bloom stage. Provides bare-ground control suitable for roadsides.
WET SITES(includes riparian areas, wetlands, ditch banks, irrigated agriculture)
2, 4-D (labeled for use next to water) Up to 2 pounds per acre Weedar 64®


Amine 4®
2 quarts per acre

2 quarts per acre
Spray at bud to early bloom stage; when using a wipe applicator, apply when plants are knee height or shorter.
Glyphosate (labeled for use next to water) 1 pound per acre Rodeo® 1 quart per acre Mow plants at bud to early bloom stage; allow plants to regrow to bud/early bloom stage; then apply glyphosate. Method has not be tested in Nevada.
1Brand names are used as examples only. Other brands may also be licensed for use in Nevada. Information herein is offered with no discrimination. Listing a commercial product does not imply an endorsement by the authors, University of Nevada Cooperative Extension or its personnel. Likewise, criticism of products or equipment not listed is neither implied nor intended. University of Nevada Cooperative Extension and its authorized agents do not assume liability for suggested use(s) of chemicals herein. Pesticides must be applied according to the label directions on the pesticide container to be lawfully and effectively applied.

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