Herbicides have been used to control this and other thistles for many. From the united states national agricultural library. Large, dense infestations where other control methods are not costeffective. Any plan relying on the use of the musk thistle head or rosette weevil needs to be approved by the kansas department of agriculture. Rosettes formed the first year and bolt early in may to june of the next year.
In locations where the weevils can multiply rapidly, a dramatic decline in musk thistle may be possible in as little as 2 to 3 years. Biological control of musk thistle integrated crop management. The thistle head weevil can reduce musk thistle populations by 90 to 95 percent in eight to 10 years after they have established. Biological control of musk thistle auburn university. Musk thistle whitman county washington state university. By 1997 it was detected in 37 counties in missouri. In addition, a rust fungus puccinia carduorum jacky uredinales. This successful biological control of musk thistle is partly due to the good synchronization of plant growth and insect activity. Bill will assume the lead role on the red gum lerp psyllid. Mechanical and manual hand pulling is most effective on small populations and can be done throughout the year, but is most effective prior to the. These biological control agents aid in reducing populations of the thistle. Biological control is a longterm approach to musk thistle control. University of nebraskalincoln extension ec176 revised.
It invades many types of habitats but is a serious threat to pastures as it is unpalatable to livestock. This successful biological control of musk thistle is partly due to the good synchronization of. It is larger and will be more difficult to control than musk thistle. In the early 1960s, staff of the usda intensively surveyed carduus spp. L873 biological control of musk thistle in kansas ksre bookstore. The first bio control release in south dakota was in the early 1970s when the musk thistle seed weevil, rhinocyllusconicus, was released to control musk thistle. Control options include mechanical, biological, cultural, and. In areas of nebraska where the weevils are present an 80 to 90percent reduction in thistle population has occurred.
In italy, larvae of the syrphid fly, cheilosia corydon harris grossa fallen, infest the flower buds, stems, and roots of carduus nutans l. Two biological control agents introduced for control of musk thistle are the thistle head weevil rhinocyllus conicus froelich and the rosette weevil trichosirocalus horridus panzer. The seed weevil rhinocyllus conicus was introduced from eurasia to control musk thistle by reducing seed production. This weed infests more than three million acres in the state.
In my random examinations of musk thistle patches over the past decades i would estimate that musk thistle weevil is present at more than half of the. The first biocontrol release in south dakota was in the early 1970s when the musk thistle seed weevil, rhinocyllusconicus, was released to control musk thistle. Thus, the goal of any control program is to reduce andor eliminate seed production. Establishing a dense, wellmaintained pasture is effective in preventing a musk thistle infestation. The head weevil works best in isolated areas where disturbance by people or ani mals is restricted and use of herbicides or cultural control methods is limited. Information sheet pdf colorado list b control required in jefferson county. Control options include mechanical, biological, cultural, and chemical methods. A seed eating weevil, rhinocyllus conicus, is quite. Musk thistle control missouri department of conservation. Origin, distribution, and life history of musk thistle. We are thrilled to welcome syed and pat to the biological control program. Herbicides have been used to control this and other thistles for many years. Biological control can be used to control targeted weed species.
Classical biological control of nodding and plumeless thistles. This thistlehead weevil was the first insect introduced into north america for the biological control of musk or nodding thistle. Kansas department of agriculture, plant protection and weed control and others to work together to document, promote, and preserve musk thistle biological. This paper addresses the benefits and risks of using biological control as a component of an ipm program directed against musk thistle in the southeastern u. Typically, it takes 6 to 10 years after weevil release to see a significant impact on the thistle population. A strain of puccinia carduorum jacky, an autoecious rust fungus from turkey, was evaluated for biological control of musk thistle carduus thoermeri weinmann in a 3year field trial. Biological control of musk thistle m usk thistle, carduus nutans, was introduced into the eastern united states in the 1800s. Mowing and removing seedheads will reduce populations of the musk thistle weevils. Combine control methods into a management system for best results. Supplemental risk evaluations and status of puccinia. The thistle head weevil can reduce musk thistle populations by 90 to. Currently there is one biological control agent released by the insectary for control of musk thistle, the musk thistle rosette weevil or crown weevil, trichosirocalus horridus. In order to reduce control costs and comply with state noxious weed laws and avoid costly fines, releases of biological control agents have been made at ioc. Cultivation in cropland will kill young musk thistle seedlings.
Biological control of the musk thistle in kansas, biological control of musk thistle in kansas. A reassessment musk thistle and nodding thistle are names commonly used to describe old world thistles in the carduus nutans species group. Buds and flowers will soon redevelop and the infestation will become greater. Musk thistle biocontrol south dakota department of agriculture.
Because the state of iowa classifies musk thistle as a. This weevil develops in the crown of the musk thistle rosette. Musk thistle plots were inoculated successfully in the fall and spring of each year. Musk thistle carduus nutans, exotic and undesirable flower heads are mostly solitary and have involucres of 24 cm tall. Grows in all soil textures, but soils must be well drained. Musk thistle, carduus nutans, was introduced into the eastern united states in the 1800s. Integrated management of invasive thistles in oklahoma. The oklahoma state legislature declared musk thistle a locally noxious weed northeastern oklahoma in 1994. The fly was studied as a candidate biological control agent of musk and italian thistle in north america. It was collected from the rhine valley in france and released in canada in 1968. University of nebraskalincoln extension ec176 revised march. Evaluation of a biological control agent for musk thistle background musk thistle carduus nutans l. Musk thistle is continuous throughout the united states.
The introduction of the musk thistle head and rosette weevils has been very effective in reducing the population in southwest missouri. Once established it spreads rapidly because of the large number of seeds produced. Biological and integrated control of musk thistle in. Request pdf classical biological control of nodding and plumeless thistles nodding musk thistle carduus thoermeri weinmann in the carduus nutans l. Apply herbicides such as tordon, vanquishclarity or 2,4d to musk thistle rosettes in spring or fall. Larvae develop in the flower head and consume the seed as it develops. Cultural, mechanical, biological and chemical control methods have all been used on musk thistles with varying degrees of success in different parts of the country. Herbicides are not as effective and there are no weevils or other insects available for biological control. Pdf successful biological control of the musk thistle in.
Species profile musk thistle carduus nutans lists general information and resources. The plants you are most likely to confuse canada thistle with are other thistles. Ethological and genetic differences among three biotypes of rhinocyllus conicus coleoptera. Musk thistle is usually a biennial, requiring 2 years to. This exotic disease of musk thistle was introduced from turkey and released in virginia in 1987. Plumeless thistle left and musk thistle right in early bloom. Curculionidae introduced into north america for the biological control of asteraceous thistles. Both surfaces appear grayishgreen due to thick cottonlike hairs. Musk thistle is often a biennial herbaceous plant in south dakota and is a highly competitive plant, threatening many desirable forage species. Test plants in the current study were evaluated in support of a proposal to use the rust in the western united states, and particularly, in california. Researchers have investigated several insects and pathogens for the control of musk thistle and some have been introduced into the united. I nsect biocontrol agents have been released on both musk thistle and canada thistle with limited success.
The targeted species in southwest missouri is the musk thistle. While they dont eliminate musk thistle, they have made it more like a native thistle. Mechanical, biological and chemical methods are some of the effective methods available for control of musk thistle. March 31, 2015 musk thistle control nebraska extension. Perennial and biennial thistle control w799 publications. Apply ally or telar up to the early flower growth stage. Musk thistle is a noxious weed in all counties in kansas. The common, weedy thistles in pa include bull thistle cirsium vulgare, musk thistle carduus. Musk thistle weevil egg masses on a musk thistle seedhead. Evaluation of a biological control agent for musk thistle. These weevils are increasing and continuing to disperse naturally. Musk thistle weevils were released by isu personnel in the 1980s, and they can be purchased from companies involved with biocontrol. A third biological control agent for musk thistle is a rust fungus.
Thistles in oklahoma and their identification oklahoma. Successful biological control of the musk thistle in oklahoma using the musk thistle head weevil and the rosette weevil. It was first recorded in the united states in 1852 at harrisburg, pa. Negative ecological effects of the musk thistle biological. Flower heads have involucral bracts that are broadly triangular more than 2mm wide, have smooth margins, and a short spinetip. Jun 08, 2017 musk thistle weevil egg masses on a musk thistle seedhead. Musk thistle and nodding thistle are names commonly used to describe old world thistles in the carduus nutans species group family asteraceae. Musk thistle and specific controls common weeds noxious. Impact of biological control agents on musk thistle. Without these natural checks, musk thistle is more prolific and competitive.
Canada thistle grows in dense patches and reduces the vigor and establishment of grassland plantings and riparian buffers that are planted to improve wildlife habitat. The key to successful musk thistle control is to prevent seed production. Russian thistle puncture vine musk thistle yellow and dalmatian toadflax bull thistle canada thistle russian knapweed purple loosestrife biological controls are most useful for reducing seed production or weakening plants. Nodding thistle biological control is achieved in about 56 years in virginia, missouri, and montana. The weevils lay eggs on the bracts of the developing musk thistle flowers. Classical biological control of nodding and plumeless. Musk thistle flower with large brown bracts and the tendency to nod or lean because of the large size of the flower. Plumeless thistle left and musk thistle right in early. Recommended practices in natural communities of high quality. Several nontarget native thistle species also supported populations of in t.
Musk thistle is an introduced invasive broadleaf weed native to europe, siberia, asia minor and north. The thistle seed head weevil, rhinocyllus conicus, is very effective in reducing seed production in this biennial weed. Biological control of musk thistle in the southeastern united. Musk thistle is a biennial weed that reproduces only from seed. Pucciniaceae has been introduced and established for control of nodding thistle in virginia. Musk thistle was among the first 19 weeds selected for biological control when the usda overseas laboratory was established at rome, italy in 1959. Field evaluation of puccinia carduorum for biological control. It is widely distributed in alabama and is a serious weed in pastures, roadsides, and waste areas idle ground. The first documented report of musk thistle in kansas was from a collection made in washington county ini 1932. Musk thistle seeds are dispersed by wind blown pappus. Refusing to buy hay that contains musk thistle seed can help prevent musk thistles from becoming established on your farm. Musk thistle rosette, which often grows 2 feet or more in diameter, with no pubescence on the underside of the leaf, which helps distinguish it from plumeless thistle rosettes.
Biological control biological control,the practice of using natural enemies,can reduce musk thistle populations and reduce the spread of musk thistles. Kansas state university agricultural experiment station and. Apply ally or \ telar up to the early flower growth stage. Compositae, both serious weeds in the united states. These include carduus macrocephalus desfontaines bigheaded thistle, c. Sud morishita, former bonneville county, idaho weed supervisor, estimates that biocontrol has reduced the countys use of chemicals to fight musk thistle by as much as 60 percent. Last, bill roltsch was transferred from imperial county to sacramento.