With the exception of very low rates of 2,4-D (0.5 to 1.0 pt/acre) applied in December or February, every other commonly used pasture herbicide will severely injure or kill clovers. As October approaches and harvest starts, don’t forget about thistles plaguing your pastures. Its notorious prickles can render otherwise grazeable land useless. Herbicide treatment can provide the most effective thistle control to maximize grass forage production. It is not able to be grazed due to the fact that it is unpalatable to livestock and wildlife. Thistles have developed their spiky leaves as a defence mechanism against grazing herbivores and they can quickly swamp a grazing paddock or lawn – out-competing grass and reducing available forage. When treating in grass pastures, ensure the pasture is slightly grazed and then after seven days treat with Lontrel Advanced + MCPA amine by boom application. UNL web framework and quality assurance provided by the, Apply to the University of Nebraska–Lincoln, Give to the University of Nebraska–Lincoln, Institute of Agriculture and Natural Resources, Strengthening Nebraska's Agricultural Economy, Nevin Lawrence - Integrated Weed Management Specialist, Chris Proctor - Weed Management Extension Educator. susceptible to MCPA* herbicides. Figure 1. The Alabama Canada thistle is a creeping perennial that can be controlled with fall spraying, in conjunction with other management options in the spring. Thistles are not difficult to control with herbicides when they are treated at the proper stage of growth, but once they bolt and send up that woody stalk, control is not so easy, so treating thistles while they are in the immature rosette stage is critical. No guarantee, endorsement, or discrimination among comparable products is intended or implied by the Alabama Cooperative Extension System. Control by grazing alone requires intensive grazing of the young, soft, aerial thistle shoots in spring, not usually possible because of pasture feed surpluses during that time. Always read and follow the label before applying any herbicide. Control. One of the biggest issues with pasture herbicides is that they are very effective clover killers too. Fall, specifically October and early November is a key time to chemically control thistles in pastures. Using good cultural practices (including rotational grazing, maintaining optimal soil fertility, and periodic mowing) that result in vigorous, dense, and uniform stands will help keep pastures competitive with weeds. Apply in the spring before early bloom for annuals or biennials, during bud stage for perennials, or treat active growth or regrowth in the fall. However, temporary yellowing, seed suppression, and stunting may occur. Proper identification of thistles is key to picking the proper chemical control. Both winged thistle and nodding thistle often have faint whitish patterns on their leaves in the rosette stage. GrazonNext® HL, Milestone®, Chaparral®, Graslan® L, Stinger®, Overdrive®, and Tordon 22K® are all products that are labelled for use on biennial thistles as well as Canada thistle. 2,4-D mixed with dicamba is also an effective option, but should be sprayed when temperatures are warmer for the highest efficacy. Musk thistle has large, nodding, solitary flower heads with wide, single spine-tipped bracts that curve upward. growing in the first place. Dr. Wilson reported that fall herbicide applications caused changes in sugars stored in the roots of Canada thistle, and decreased the chances of the weed surviving the winter. In Nebraska we have several biennial thistles, but we mostly deal with musk, plumeless, Scotch, and bull thistles in our pastures. Those old stories about grandpa spending his winter days grubbing thistles, here appear to have merit. Another thistle to look out for is Canada thistle. This is an ideal time to control biennial and perennial thistles. Start by identifying your pasture weeds, says Bradley. Please review our Privacy Statement for more information. Sept. 25, 2015. This persistent weed often sneaks up on producers in spring and can quickly take over a pasture. Several of the herbicides listed above will injure or kill forage legumes. Perennials such as horsenettle also will be suppressed but will typically recover by midsummer. Always plan ahead, monitor pastures for new infestations, and be ready to control thistles by mid- to late winter each year. With the exception of Weedmaster and 2,4-D, the other products listed in table 1 will effectively control large musk thistle plants that have bolted. Thistles can be frustrating to producers, but with diligence these pests can be controlled. The good news is that the herbicides available to control thistle will also control many of the winter annual weeds that are out there right now in Panhandle pastures and hayfields. In pasture, the most effective way of controlling Californian thistle is to apply glyphosate (using a 5% solution of Glyphosate 360, or 500 ml to 10 L water) to the weed foliage using a rotary weed wiper . This website would like to use cookies to collect information to improve your browsing experience. This content printed from the website located at: Thistle Control in Pastures and Hayfields. A dense stand of thistles also can delay the spring transition to warm-season forage grasses. A single thistle plant can produce at least 4,000 seeds, which increases the chance for higher thistle populations in the pasture the following year. In many areas, spot treatment of Canada thistle provides suicient control of thistle … When it is in this stage all of the options (mechanical, chemical, and manual) are available to you. No control strategy should rely on herbicide use alone and needs to be integrated, particularly with good grazing practice and mechanical topping if it is to be effective (see Table 1). Most of the herbicides used for control of thistles also kill desirable forbs, so spot spraying individual plants or patches rather than broadcast spraying the entire pasture can spare valuable forbs. See our factsheet for detailed information on biennial thistle control. Regardless of the control method selected, the importance of timing cannot be over emphasized. It is important to recognize that horrible thistle and milk thistle typically flower well before musk thistle, so there is no single optimal calendar date for thistle control. When choosing an herbicide for spraying thistles, the proximity of thistles to waterways and sensitive plants, grazing and haying restrictions, and the type of thistle are all important considerations. Source: Management of Canada Thistle in Pasture; AARI 2005. It is not necessary to dig out the entire taproot. Control of Canada Thistle in CRP and Other Noncrop Acreage • FNR-436-W Herbicides that are efective on Canada thistle will injure or kill most broadleaf plants (including legumes) and glyphosate will injure or kill grasses. Limited control can be achieved with mowing. Fall, specifically October and early November, is a key time to chemically control thistles in pastures. Identifying thistles when they are in the rosette stage can be extremely difficult. Stems are winged and spiny. Some thistles even release chemicals into the soil that inhibit the growth of other plants. Milk thistle has solitary flower heads with stiff, spiny bracts that often curve downward. Creeping or field thistle control 21. In NSW, Scotch thistle is a major weed of pastures on the Central and Southern Tablelands and the Central and South-West Slopes. One year of poor thistle control will result in having to start the control program over. This is an ideal time to control biennial and perennial thistles. Although thistles attract pollinators and birds, the spiny leaves and stems keep grazers away. Table 1. Proper identification of thistles is key to picking the proper chemical control. Spot spraying individual plants or patches rather than broadcast spraying the entire pasture also spares the legumes. Musk thistle or nodding thistle (Carduus nutans) is the most aggressive nonnative thistle in Alabama. Find answers to controlling thistle growth and spread in these frequently asked questions. While there are several herbicides that are effective on large, bolted thistle, the spring forage response will be decreased the later you wait to spray. While the summer-blooming thistle flower (1a, left) may be the most recognizable growth form, scout now for the small, flat rosette stage (Figure 1b) and treat with herbicides this fall to achieve the most effective control. Download a PDF of Thistle Control in Pastures and Hayfields, ANR-2149. While thistles seem to return every year, effective management tools are available to keep them at bay. Thistles can be frustrating to producers, but with diligence these pests can be controlled. Two musk thistle bio-control insects have been distributed throughout much of Alabama. Treat in late winter or early spring when thistles are still rosettes to maximize spring forage production. Fall, specifically October and early November, is a key time to chemically control thistles in pastures. See table © 2021 by the Alabama Cooperative Extension System. Take care when purchasing products and always read/follow label directions before use. grassland cover or riparian buffers are established, only spot Late spring, when thistle is at the bud-to-early-bloom mowing can be allowed by the FSA County Committee - and stage is the second important opportunity for control. The best preventive measure in noncropland is to maintain a thick plant cover and reseed disturbed areas with a desirable species as soon as possible. Thus, treatments to control musk thistle need to be made prior to legume establishment. It is important to note that fall spraying of thistles is not a silver bullet and effective control often needs repeated applications. The deep, creeping roots send new shoots popping up along lengths that extend up to 20 feet, making the weed difficult to control once it takes hold. All rights reserved. Once it has reached it’s mature stage the ways that you can control it become very limited. Grass sods for pasture, conservation reserve and ground cover --Clopyralid STINGER at 2/3 pt/acre. Plant weed-free seed to help prevent introduction into cropland, and keep field borders thistle-free. )Over the past two summers, Bradley’s graduate student, Zach Trower, has walked across 46 Missouri pastures every 14 days to record weed species, estimate densities, and sample soil. Thistles are a common weed problem throughout Alabama. that ensures all people have access to information that improves their quality of life Thistle species in Nebraska. Mow or cut the thistle … Biennials require portions of two growing seasons to flower/reproduce. Both can have substantial impacts on thistle seed production. and economic well-being. Dense populations of thistles may have to be controlled in sta… The use of tradenames is for educational purposes only and not an endorsement. Several products are effective for all thistles, but some herbicides have higher efficacies depending on the thistle species. Rating one year after Canada thistle treatment in 2000. Figure 3. For more complete control in grass only pastures, use ForeFront or Chaparral. Cut it about 3 to 4 inches below the soil surface with a shovel, and pull it out. Much only approved on an annual basis. These thistles do not have creeping roots and produce new shoots. Stems are covered in fine hairs and hairlike projections. However, combining mowing or a herbicide application with grazing can provide a wider window for control. Some parts of this site work best with JavaScript enabled. Written by Stephen Enloe. Canada thistle control with weed wiping at three pasture sites in central Alberta. Once established thistles are difficult and expensive to control. Where is it found? However, these low rates of 2,4-D are not effective on established thistle rosettes. More herbicides can be used and the small size of musk thistle seedlings and new growth of Canada thistle is key to effective chemical control. Turn some horse4s out in a thistle patch in a rain storm and they will kill alot of it. Scotch thistle is a native of Europe, western and central Asia. The rosette overwinters and the cold causes the rosette to bolt the next season and produce seed. 2Grazon P+D and Surmount are both “restricted use” herbicides. Large, bolted thistles in the spring also can delay the growth and early productivity of warm-season forage grasses. Soybeans (at leaf drop) preharvest with glyphosate ROUNDUP 1 qt/acre. Visit www.aces.edu/directory. Thistle Species in Nebraska . MCPA (Rhonox) is safer than most herbicides on legumes, but may still cause injury. using herbicide treatment; spear thistle is susceptible to clopyralid * and moderately . Reviewed by Dr. Leanne Dillard, May 2019. However, new shoots will emerge from buds in the leaf axils below the mowing heights and will flower and produce seed. For more information, contact your county Extension office. It will take several years of timely control before the soil seed bank is reduced. Their aggressive and spiny growth shades out grasses and clovers and deters cattle from grazing infested areas. Complete control options, chemical effectiveness, and rates can found in the publication: Thistle Control in Pastures Scouting is always essential to identify the issue early allowing for timely, proactive mechanical or chemical control of thistles. Since musk thistle seed can survive in the soil for a number of years, it may take two or more years of excellent control before seeds are reduced to the point that allo… Mechanical and chemical control can be effective for thistles in pastures. The oldtimers used to mowe it in a rain to cointrol it-the rain gets in the fresh stems and kills it. Control measures include 2,4-D, Weedmaster (2,4-D+dicamba) or their generic alternatives, GrazonNext, Pasturegard, Remedy Ultra, or metsulfuron. Flowers are yellow or reddish purple and rarely white. Everyone is welcome! Musk thistle flower head (left). Corn --A clopyralid and flumetsulam combination sold as HORNET is less costly and next most effective to STINGER for selective control of Canada thistle in normal corn. The sharp spines can prevent access to both livestock and people. Using a shovel to dig thistles during the rosette stage is a common practice of control in pastures during early infestation. Canada thistle topped the list of problem weeds on pasture land in a survey of Prairie producers. 1 for recommended treatments. For more extensive thistle infestations, it is recommended to use Grazon Extra at 150 mL per 100 L of water (1.5 mL per 1 L) as a foliar spray with a knapsack or 12 volt sprayer. If left uncontrolled, thick thistle stands can reduce grazing, result in less forage production, and ultimately lower calf weaning weight. Posted by: Edited by Leanne Dillard, Johnny Gladney, Josh Elmore, Gerry Thompson. Yellow thistle has large, clustered flower heads with spiny, feathery bracts that almost enclose each flower’s entire head. Choosing the right products for your program is another key step to controlling your thistles. When trying to control biennial thistles, destruction of rosettes prior to flowering (bolting) is an effective means of preventing seed formation and subsequent spread. Most of the herbicides used for control of bull and musk thistle also kill pasture legumes. Yellow thistle, also known as horrible thistle (Cirsium horridulum), is native and abundant throughout much of the state. Milk thistle (Silybum marianum), another exotic, is occasionally found in Alabama as a pasture weed. 105 Ag. 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