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. Where is it found? Sept. 25, 2015. Download a PDF of Thistle Control in Pastures and Hayfields, ANR-2149. These thistles do not have creeping roots and produce new shoots. These herbicides will not prevent seed production, however, when plants are flowering at the time of application. growing in the first place. Rating one year after Canada thistle treatment in 2000. Fall, specifically October and early November, is a key time to chemically control thistles in pastures. In many areas, spot treatment of Canada thistle provides suicient control of thistle … Find answers to controlling thistle growth and spread in these frequently asked questions. Soybeans (at leaf drop) preharvest with glyphosate ROUNDUP 1 qt/acre. 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. Additionally, waiting until after clovers seed before spraying is difficult to do as most thistles will have gone to seed before the clover. In Nebraska we have several biennial thistles, but we mostly deal with musk, plumeless, Scotch, and bull thistles in our pastures. 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. It is important to note that fall spraying of thistles is not a silver bullet and effective control often needs repeated applications. No guarantee, endorsement, or discrimination among comparable products is intended or implied by the Alabama Cooperative Extension System. Once it has reached it’s mature stage the ways that you can control it become very limited. Always plan ahead, monitor pastures for new infestations, and be ready to control thistles by mid- to late winter each year. 105 Ag. Both products will kill woody plants. 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. )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 may take an entire month to die when sprayed at the bud stage. Two musk thistle bio-control insects have been distributed throughout much of Alabama. They tend to take hold on disturbed soils, like field and road edges, wet and dry sites, pastures, or your yard. 1 for recommended treatments. Proper identification of thistles is key to picking the proper chemical control. Creeping or field thistle control 21. 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. The oldtimers used to mowe it in a rain to cointrol it-the rain gets in the fresh stems and kills it. However, new shoots will emerge from buds in the leaf axils below the mowing heights and will flower and produce seed. It will take several years of timely control before the soil seed bank is reduced. Some parts of this site work best with JavaScript enabled. Visit © 2021 by the Alabama Cooperative Extension System. 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. Scotch thistle is a native of Europe, western and central Asia. The key to managing thistles is control of seed set. 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). Fall, specifically October and early November, is a key time to chemically control thistles in pastures. that ensures all people have access to information that improves their quality of life Note that some products traditionally recommended for spraying thistles have recently changed product names. It is not able to be grazed due to the fact that it is unpalatable to livestock and wildlife. susceptible to MCPA* herbicides. 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. Some thistles even release chemicals into the soil that inhibit the growth of other plants. 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. Spot spraying individual rosettes rather than broadcast spraying the entire pasture also spares the legumes. If left uncontrolled, thick thistle stands can reduce grazing, result in less forage production, and ultimately lower calf weaning weight. Where clover is an important constituent of the sward, a mixture of MCPA* and MCPB* herbicides is more appropriate. Control measures include 2,4-D, Weedmaster (2,4-D+dicamba) or their generic alternatives, GrazonNext, Pasturegard, Remedy Ultra, or metsulfuron. Mow or cut the thistle … “We have a smartphone app and a booklet to help,” he says. Turn some horse4s out in a thistle patch in a rain storm and they will kill alot of it. 2Grazon P+D and Surmount are both “restricted use” herbicides. and economic well-being. Aug 16, 2006 | 10:17 5 We actually controlled a bad thistle patch by accidant in the last drought-lost the water in one pasture so gave it a year off-the thistle was almost gone the next year. Much only approved on an annual basis. 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. Proper grazing management and rotational grazing practices should be established and maintained to p… Proper identification of thistles is key to picking the proper chemical control. Musk thistle flower head (left). The rosette overwinters and the cold causes the rosette to bolt the next season and produce seed. The sharp spines can prevent access to both livestock and people. Once established thistles are difficult and expensive to control. Figure 1. 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… 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. An integrated management program is the key to successful thistle management. For more information, contact your county Extension office. Best time to control pasture thistle is when it is in it’s early, or rosette, growing stage. Reviewed by Dr. Leanne Dillard, May 2019. Milk thistle has solitary flower heads with stiff, spiny bracts that often curve downward. Thistle Species in Nebraska . Use instructions: - Apply 3 to 5 oz/A Milestone postemergence to control musk and plumeless thistle, 4 to 6 oz/A for tall Dense populations of thistles may have to be controlled in sta… This is an ideal time to control biennial and perennial thistles. Dense thistle populations can reduce property values. 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. Milk thistle (Silybum marianum), another exotic, is occasionally found in Alabama as a pasture weed. Both winged thistle and nodding thistle often have faint whitish patterns on their leaves in the rosette stage. Cooperative Extension System. Fall, specifically October and early November is a key time to chemically control thistles in pastures. Timing of thistle control is crucial and the method used will vary according to the site. Proper identification of thistles is key to picking the proper chemical control. Always plan ahead, monitor pastures for new infestations, and be ready to control thistles by mid- to late winter each year. MCPA (Rhonox) is safer than most herbicides on legumes, but may still cause injury. The use of tradenames is for educational purposes only and not an endorsement. Thistles often invade overused or disturbed land, such as cultivated fields. One of the biggest issues with pasture herbicides is that they are very effective clover killers too. Trade and brand names used in this publication are given for information purposes only. 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. Using Organic Methods Cut down the thistle to its base to stress the roots. The best time to dig or hand-pull thistles is when they have bolted but not yet flowered. Fall applications are extremely effective on thistle rosettes. Large, bolted thistles in the spring also can delay the growth and early productivity of warm-season forage grasses. 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. Stems are winged and spiny. 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. Control nettles by cutting repeatedly since this will weaken them. The use of a range of tools such as the maintenance of a strong perennial pasture, strategic herbicide application, chipping by hand and use of biological control agents where appropriate is the best strategy for long term control. When trying to control biennial thistles, destruction of rosettes prior to flowering (bolting) is an effective means of preventing seed formation and subsequent spread. See our factsheet for detailed information on biennial thistle control. Using herbicide is no longer an option at this stage. Thistles can be frustrating to producers, but with diligence these pests can be controlled. Flowers are purple, and the stems are hairless and not winged. Musk thistle or nodding thistle (Carduus nutans) is the most aggressive nonnative thistle in Alabama. 1. Control Pasture Thistles this Fall Share Tweet Email. Everyone is welcome! Musk thistle has large, nodding, solitary flower heads with wide, single spine-tipped bracts that curve upward. Canada thistle is a creeping perennial that can be controlled with fall spraying, in conjunction with other management options in the spring. Always read and follow all label directions. However, combining mowing or a herbicide application with grazing can provide a wider window for control. The Alabama Cooperative Extension System (Alabama A&M University and Auburn University) is an equal opportunity educator and employer. Always read and follow the label before applying any herbicide. Mechanical and chemical control can be effective for thistles in pastures. The Alabama Posted by: Edited by Leanne Dillard, Johnny Gladney, Josh Elmore, Gerry Thompson. It is not necessary to dig out the entire taproot. After flowering or with the first frost, biennial thistles die in the second year. For more complete control in grass only pastures, use ForeFront or Chaparral. Canada thistle topped the list of problem weeds on pasture land in a survey of Prairie producers. They develop from seed the first season as a flat rosette (Figure 1). Bull thistle (Cirsium vulgare) is very uncommon, and Canada thistle (Cirsium arvense) is extremely rare, if at all present. Alabama Its notorious prickles can render otherwise grazeable land useless. This is an ideal time to control biennial and perennial thistles. 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. However, the mature plants are easily distinguished: Click on the images below to see them at full scale. However, soil residual herbicides may not provide complete control through the next summer. 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. Thistles are a common weed problem throughout Alabama. Flowers are deep rose to violet or purple and very rarely white. By preventing plants from ripening seed the following year’s population will be greatly reduced. Do you accept? 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. Thistle species in Nebraska. 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. Please consult this factsheet for more information on control of this problematic species in pastures. There are many herbicides labeled for thistle control. Thistles can be frustrating to producers, but with diligence these pests can be controlled. Limited control can be achieved with mowing. Source: Management of Canada Thistle in Pasture; AARI 2005. Year of treatment 2000. This website would like to use cookies to collect information to improve your browsing experience. Choosing the right products for your program is another key step to controlling your thistles. Distaff thistle as well as the other species of thistle are considered the most serious threat to range and pasture. Fall, specifically October and early November, is a key time to chemically control thistles in pastures. Communications Bldg.Lincoln, NE 68583-0918. Thus, treatments to control musk thistle need to be made prior to legume establishment. For Canada thistle, control is more challenging. This content printed from the website located at: Thistle Control in Pastures and Hayfields. Both can have substantial impacts on thistle seed production. Fall is a key time to target these rosettes and to help mitigate seed production the following season. Yellow thistle, also known as horrible thistle (Cirsium horridulum), is native and abundant throughout much of the state. Download a PDF of Thistle Control in Pastures and Hayfields, ANR-2149. 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 . Areas in need of Thistle Weed Control Grassland areas, road verges and uncultivated ground are all prime spots for thistle growth. Spot spraying individual plants or patches rather than broadcast spraying the entire pasture also spares the legumes. When it is in this stage all of the options (mechanical, chemical, and manual) are available to you. 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. Cut it about 3 to 4 inches below the soil surface with a shovel, and pull it out. In NSW, Scotch thistle is a major weed of pastures on the Central and Southern Tablelands and the Central and South-West Slopes. See table Flowers are yellow or reddish purple and rarely white. truly effective Canada thistle control products (Table 1). Previous research from Robert Wilson (UNL Emeritus Professor) indicated that control of Canada thistle went from 33%, when an herbicide was applied in the spring, to 90%, when fall applications were made. Plant weed-free seed to help prevent introduction into cropland, and keep field borders thistle-free. Mechanical control can be effective, especially in smaller pastures, or when issues first arise, and there is a small infestation. The optimal time for mowing is when thistles reach the late bolting stage when flower buds begin to emerge. 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. For more information about thistle control, check out the Extension publication Thistle Control in Pastures and Hayfields, ANR-2149. 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. Biennials require portions of two growing seasons to flower/reproduce. Herbicide treatment can provide the most effective thistle control to maximize grass forage production. Using a shovel to dig thistles during the rosette stage is a common practice of control in pastures during early infestation. When using Tordon 22K® or Graslan® L, both products are redistricted use and contain picloram, use extreme caution around other vegetation, especially trees. Regardless of the control method selected, the importance of timing cannot be over emphasized. Those old stories about grandpa spending his winter days grubbing thistles, here appear to have merit. 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. This is an ideal time to control biennial and perennial thistles. Thick stands can completely crowd out other vegetation reducing grazing.