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