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Novelty, Knox County
Field Day
*Our next Field Day will be held August 7, 2008
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Randall Smoot
P.O. Box 126
Novelty, MO 63460
Phone: 660-739-4410
Email: SmootR@missouri.edu
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Teasel: A Noxious Weed Invading Roadsides in Missouri
Diego J. Bentivegna
Graduate Student |
Reid J. Smeda
Associate Professor |
Background:
Common teasel (Dipsacus sylvestris) and cutleaf teasel
(Dipsacus laciniatus) are invasive weeds introduced from
France into the NE part of the US during the 1700’s. Both
plants were used originally in the textile industry for
"teasing" the knots in wool prior to spinning. When
mechanical methods were developed for wool, teasel was
no longer used and was abandoned as a crop. However,
teasel began to spread from the NE and followed many
highway corridors. In addition, teasel was desirable as a
dried flower and used as such in cemeteries. All of these
methods of dispersal have contributed to greater
populations of teasel. Today, teasel has been identified in
all 48 continental US states, and was declared a noxious
weed in Missouri in 2000.
Biology:
Both common and cutleaf teasel are biennials, with peak emergence of seedlings occurring in
early fall or spring. Basal rosettes grow up to 22 inches in diameter, and populations form dense
communities. This contributes to teasel crowding out native vegetation such as fescue. If
seedlings emerge in the fall, plants will survive for two winters. For spring emerging seedlings,
rosettes only survive one winter. Following winter, plants bolt and reach up to 2.5 meters in
height.
Research objectives:
- Understand the biology and reproductive capabilities of cutleaf teasel under Missouri
conditions.
- Identify seed viability following initial flowering.
- Determine if the timing of mowing impacts teasel seed production.
- Examine the use of different herbicide programs for managing teasel.
Preliminary results:
A survey of the literature suggests that teasel produces up to 3,000 seeds per plant. Our initial
results reveal that plants growing in the absence of other plants produce up to 13,200 seeds,
while plants in close proximity to other plants produce up to 3,800 seeds. Concerning flowering,
viable seeds are first detected in as little as 12 days following flowering, which suggests that
mowing plants during flowering may not be a practical method for teasel management. When
plants are mowed when flowering just begins, regrowth occurs for plants, but viable seeds are
not produced. It is not known if mowing plants when bolting first occurs will lead to regrowth in
a sufficient time period such that viable seed are produced. There are only two registered
herbicides for control of teasel, but agronomically acceptable control of teasel was determined at
60 days following treatment for: glyphosate, dicamba + diflufenzopyr, 2,4-D + triclopyr, 2,4-D
+ picloram, 2,4-D + clopyralid, metsulfuron-methyl, imazapyr, and sulfometuron-methyl.
2006 Field Day Report
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