Musk Thistle Control Program

Musk Thistle Control Program June 1, 2000

( This plant has a distinctive gray or silver edging to its leaves even at the seedling size)

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. 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 ½ 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 may be found throughout the State with heaviest infestations found in the north eastern one third of the State. Musk thistle only reproduces by seed. The likelihood of new infest-ations 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

Mowing - Mow with a rotary mower between the first appearance of pink and the 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 the 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. Always read and follow label directions.

2,4-D Amine or LV Ester
Chlorsulfuron (Telar)
Dicamba (Banvel, Clarity, Vanquish)
Dicamba + 2,4-D
Picloram (Tordon)
Picloram + 2,4-D
Metsulfuron Methyl (Escort)
Metsulfuron Methyl + 2,4-D
Imazapic (Plateau)
Clopyralid + Triclopyr (Redeem R+P)
Triasulfuron + Dicamba (Rave)

Per acre costs for these chemicals can be obtained from the Marion County Weed Office at 620-382-3190 or emailing jhousman@marioncoks.net

BIOLOGICAL CONTROL PLAN

Any biological control plan must meet the requirements of K.A.R. 4-8-41.