Kudzu Field Bindweed Russian Knapweed Hoary Cress Canada Thistle Quackgrass

Leafy Spurge Bur Ragwood Pignut Musk Thistle Johnsongrass

Musk Thistle

Official Control Program

Description

Musk thistle is primarily a biennial or winter annual but may occur as a summer annual. The leaves of musk thistle are deeply lobed, hairless, and are dark green with a light green mid-rib. A silver gray leaf margin is characteristic of each spine tipped lobe.

The leaf base extends down the stem to give the plant a winged appearance. Musk thistle is the first of the Kansas thistles to bloom in the spring. The terminal flower is large (1 1/2 to 3 inches in diameter), solitary and usually nodding or bent over slightly. The plant is freely branched and each branch may have one flower or more in addition to the terminal flower. The flowers are purple and are "powder puff" shaped. Seed dispersal begins 7 to 10 days after blooming. Seeds are straw- colored, oblong, and 1/8 inch in length.

The seeds are attached to parachute-like hairs (pappus) which allow for their dispersal by wind currents.

Prevention of Spread of Musk Thistle

Musk thistle is distributed throughout all of the State but a few southwest Kansas counties.

Musk thistle reproduces only by seed. The likelihood of new infestations will be reduced by any action to prevent the production and movement of seed. Planting weed free seed, feeding hay free of musk thistle seed and cleaning equipment before leaving infested areas are methods which will prevent the spread of musk thistle.

Musk Thistle Control Practices

The control of musk thistle shall mean preventing the production of viable seed.

Cultural Control Practices

Mowing - Mow with a rotary mower between the first appearance of pink and the first appearance of brown on the pappus of the earliest heads. Mow cleanly and closely and repeat as needed for control.

Hand Cutting - Digging - Cut between the first appearance of pink and the first appearance of brown on the pappus of the earliest head. Dig the root at least two inches below ground level and remove all soil from the roots. Pick heads that are beyond the bud stage and place in a tight container. Bury the container at a landfill or other site that will not be unearthed.

Herbicides Approved for Controlling Musk Thistle

The following herbicides may be used for cost-share with landowners. Other products labeled and registered for use on this noxious weed in Kansas may be used in accordance with label directions but are not available for cost-share.

2,4-D Amine or LV Ester. Apply during rosette stage of growth. 2,4-D Amine can be used in the fall if the soil moisture is favorable and air temperature exceeds 50 F. Follow label directions and precautions.

Chlorsulfuron (Telar). Apply in spring from rosette to prebloom stages of growth. Follow label directions and precautions.

Dicamba (Banvel). Apply in spring during rosette stage of growth. Can be used for control in fall if the soil moisture is favorable and air temperature exceeds 50 F. Follow label directions and precautions.

Dicamba + 2,4-D (Banvel + 2,4-D). Apply in spring during rosette stage of growth. Can be used for control in fall if the soil moisture is favorable and air temperature exceeds 50 F. Follow label directions and precautions.

Picloram (Tordon). Restricted use herbicide. Apply during rosette stage in spring or in the fall, prior to soil freeze-up. Follow label directions and precautions.

Picloram + 2,4-D (Tordon + 2,4-D). Restricted use herbicide. The addition of 1.0 pound of 2,4-D will improve the consistency of musk thistle control with picloram when environmental of biological conditions are not conducive to good herbicidal activity.

Metsulfuron methyl (Escort). Use rates depend on the application site. Consult the label and supplemental labels for use directions. Follow label directions and precautions.

Metsulfuron methyl + 2,4-D (Escort + 2,4-D) Use rates depend on the application site. The addition of 2,4-D will improve consistency of musk thistle control when environmental or biological conditions are not conducive to good herbicidal activity. Follow label directions and precautions.

Biological Control practices

Use of predators, parasites, disease causing organisms and other tools that provide biological control of musk thistle is approved when use is in accordance with a plan submitted by the landowner which establishes procedures for carrying out the biological program on said land. Any biological control organism shall not be used unless or until specific guidelines for its use are approved. A proposed biological control program may be implemented upon its approval by the Secretary of the Kansas State Board of Agriculture. Any proposed plan for biological control of musk thistle shall not be approved without concurrence of the County Weed Supervisor of the county in which the infestation is found.

Biological control organisms used shall be Rhinocyllus conicus and other organisms recognized by the Kansas State Board of Agriculture as being effective for musk thistle control.

To prevent spread of musk thistle to adjacent properties a minimum of 150 feet wide continuous musk thistle free border shall be maintained by application of approved cultural and or chemical controls around each location where biological control procedures are used.