Bear Lodge Project – Bull Hill Mine
January 2013
Weed Management Plan
9
jugoslavica
) are approved, effective biocontrol agents.
Cultural: Seeding desirable perennial grasses and forbs will provide competition with the
knapweed; irrigation can increase effectiveness of seeding. Grazing management
can help decrease populations.
Manual/Mechanical: Small patches can be controlled by hand pulling or digging.
Spotted knapweed
Spotted knapweed is a biennial or short-lived perennial that grows up to 3 feet tall and spreads by
seed. Rosette formed the first year with a flowering stalk elongating the second year. Stems are
erect with slender wiry bracts and are covered with fine hair. Flowering heads are mostly on branch
tips, solitary, up to one inch in diameter, and pink to purple in color, rarely white, with black tipped
seed head bracts. Leaves are long and divided below the branches and short and narrow above;
covered with fine hairs. Seeds are brownish, 1/8 inch long, notched on one side of the base, and
have short tufts of bristles at the tip.
Management Objective
: Containment
Integrated Management
Chemical: Picloram, picloram + 2,4-D, dicamba+diflufenzopyr, 2,4-D, dicamba + 2,4-D,
clopyralid, clopyralid + 2,4-D and clopyralid + triclopyr are all effective control
agents.
Biological: Banded knapweed gall fly (
Urphaora affinis
), UV knapweed seedhead fly
(
Urophora quadrifasciata
), green knapweed clearwing fly (
Terellia virens
),
knapweed peacock fly (
Chaetoreellia acrolophi
), knapweed seedhead moth
(
Metzneria paucipunctella
), lesser knapweed flower weevil (
Larinus minutes
),
blunt knapweed flower weevil (
Larinus obtusus
), broad-nosed knapweed
seedhead weevil (
Bangasternus fausti
), sulphur knapweed root moth (
Agapeta
zoegana
), brown-winged knapweed root moth (
Pterolonche inspersa
), gray-
winged knapweed root moth (
Pelochrista medullana
), knapweed root weevil
(
Cyphocleonus achates
), and bronze knapweed root borer (
Sphenoptera
jugoslavica
) are approved, effective biocontrol agents.
Cultural: Seeding desirable perennial grasses and forbs will provide competition with the
knapweed; irrigation can increase the effectiveness of seeding. Grazing
management can help decrease populations.
Manual/Mechanical: Small patches can be controlled by hand pulling or digging.
Common tansy
Common tansy is a perennial that grows erect and bushy up to 6 feet tall; reproduction is from the
roots. Leaves are dark green, alternate, deeply lobed and divided into many narrow toothed leaflets.
Stems are often purple-ish red in color. Flowers are yellow and button-like in appearance, having
no petals, ½ inch in diameter in dense clusters. Seeds are yellowish brown in color.
