Presentation on the invasive teasel.

1. Teasel: Why Is It Here and
How Do We Get Rid of It?
Reid J. Smeda and Diego J. Bentivegna
University of Missouri

2. Cut-leaf teasel
(Dipsacus laciniatus L.)

3. • Exotic- Invasive weed
(USDA)
• Declared Noxious
in Missouri, Iowa, Colorado and
Oregon
• Dipsacus is derived from
the Greek word 'dipsakos',
which means thirst

4. A sheepish beginning

5. Origin
 Introduced as a “crop” to New England from France in
1780’s; “teaseling” wool
 Abandoned in 1800’s; mechanization
 Movement follows interstate highway corridor
 Desirable as a dried flower
Teasel in Argentina, 2009

6. Biology
 Biennial, with emergence in fall and
spring
 Leaves: large, opposite, and sessile
with deep serrations
 Prickly stem and spine in the mid-rib
of the leaves
 Deep taproot : Extracts nutrients and
water from deficient soils

7. Emergence of teasel in Missouri
(Data 2003-2004)
200
180
A
Emergence (N° /meter2)
160
140
A
120
100
80
60
40
20
0
Sep Oct Nov Dec Jan Feb Mar Apr May June
Time

8. Seedling (2 months)
Pre-flowering (1 month)
Seed Rosette
Development (12 months)
(3 months)

10. Total above ground Biomass

11. Plants capable of growth late into year

12. Taproot (DW)

14. Reproductive Phase (Stem – Seedheads)

15. Methodology
 Fifteen plants growing alone and in a group (2 plants within 60
cm) were randomly selected in two locations and two years
Primary Seedhead x
x x
x
Alone Group
 Number of seedheads, seed
production of the primary seedhead,
and total seed production per plant
was evaluated
 Regression used to estimate seed
production

16. Total Seed Production per Individual Plant

17. Summary of seed production study
 Seed production is more than five times greater than was
registered in other locations (Werner 1975, Glass 1991)
 Seed production was affected by location, year, and
growth habit
 Principal seedheads produce more than 1000 seeds
 Maximum seeds produced
per plant was 33,000
 First viable seed produced
12 days following first
flowers on primary seedhead

18. Seed persistence study
 150 seeds were put in pots in 09/04 in New Franklin
and Columbia (Bradford); 5 pots harvested each
spring, summer and fall.
 Tetrazolium test was done to assess the viability.

19. If we don’t want teasel, what do we do about it?
 Fire= insufficient fuel to burn through infested areas
(Solecki 1993)
 Biological= slow and doesn’t have natural enemies in USA
(Rector 2006)
 Mechanical= - immature seeds complete maturation in stem
- plants regrowth (Solecki 1993)
5 months
 Chemical= most cost effective (Missouri Vegetation Management
Manual 1997)

20. Mowing
Determine the optimum timing to mow bolting plants:
 Mowing (15-30 July)
 Frequency (one time)
 Height (12 cm)
08/18/04

21. 10/04/04

22. 12/18/04
Plant mowed above 12 cm at
the beginning of July
Flowering on 10/04/04

23. What about control practices?
Determine the efficacy of herbicides on teasel
rosettes as well as residual activity on new
emergence
Herbicides

24. Herbicides treatments
Mode of action Herbicide Rate (kg ai ha-1) Time
- Untreated -- --
AA biosynthesis Glyphosate 2.52 Fall and Spring
Dicamba + Diflufenzopyr 0.29 Fall and Spring
2,4-D 1.68 Fall and Spring
Growth 2,4-D + Triclopyr 1.68 + 0.84 Spring
regulator
2,4-D + Picloram 1.68 + 0.45 Spring
2,4-D + Clopyralid 1.68 + 0.32 Spring
Acetolactate Metsulfuron Methyl 0.008 Spring
Synthase
inhibitors (ALS) Imazapyr 0.84 Spring
Sulfometuron methyl 0.11 Spring
Sulfosulfuron 0.11 Spring
Cell Membrane Paraquat 0.94 Spring
Disrupters

25. Environmental conditions
 Soil pH= 5.9-7.6
 Soil OM= 1.8 -2.9%
 Wind speed: < 4 mph
 Air temperature
> 8.5C in Fall
> 15C in Spring
 At 2, 4 and 8 weeks following applications, teasel plants were
visually evaluated for injury
 A scale of 0 to 100 was used: 0 = no effect and 100 = plant death
 Residual activity was evaluated in two 0.3 x 0.3 m areas in plots of
selected treatments by counting seedlings through the year

26. AA Biosynthesis Growth regulators
Membrane disrupters Acetolactate synthase

27. Evaluation 2 Weeks after treatment
Treatments Time Highway Fairground Bradford Moberly
Fall 30 def 23 cd 28 b 28 b
Glyphosate
Spring 43 bcd 88 b 59 b 65 b
Fall 34 cde 19 d 25 b 20 b
Dicamba +
Spring 43 bcd 53 b 49 b 56 b
Diflufenzopyr
Fall 24 efg 6d 13 c 15 c
2,4-D
Spring 31 de 36 b 25 b 49 b
2,4-D+Triclopyr Spring 48 bc 50 b 38 b 50 b
2,4-D+Picloram Spring 53 b 49 b 51 b 55 b
2,4-D+Clopyralid Spring 39 bcd 39 b 35 b 42 b
Metsulfuron-methyl Spring 15 fg 29 c 16 c 16 c
Imazapyr Spring 16 fg 31 c 11 c 14 c
Sulfometuron-methyl Spring 13 gh 23 c 23 c 18 c
Sulfosulfuron Spring 0h 6e 1c 5c
Paraquat Spring 95 a 95 a 86 a 88 a

28. Evaluation 8 Weeks after treatment
Treatments Time Highway Fairground Bradford Moberly
Fall 95 a 90 a 96 ab 100 a
Glyphosate
Spring 85 abc 98 a 93 ab 100 a
Fall 100 a 96 a 100 a 100 a
Dicamba + Spring 95 a 100 a 100 a 100 a
Diflufenzopyr
Fall 89 ab 96 a 66 d 83 b
2,4-D
Spring 95 a 100 a 76 cd 100 a
2,4-D+Triclopyr Spring 98 a 100 a 86 bc 100 a
2,4-D+Picloram Spring 100 a 100 a 100 a 100 a
2,4-D+Clopyralid Spring 100 a 100 a 100 a 100 a
Metsulfuron-methyl Spring 100 a 100 a 100 a 100 a
Imazapyr Spring 100 a 100 a 100 a 99 a
Sulfometuron-methyl Spring 64 c 81 b 78 cd 98 a
Sulfosulfuron Spring 0d 9c 3e 33 c
Paraquat Spring 70 bc 88 b 100 a 100 a

29. Accumulated emergence after 210 days of herbicides treatments for year 2005.

30. Remote Sensing
 Remote sensing consists of the acquisition and recording of
information about an object or interest target without touching it
Growth regulator
Advantages:
 Non destructive measurement
 Objective periodical data
 Large spatial distribution
Acetolactate Synthase

31. Data Collection and Pre- Processing
Bradford Research & Extension Center Highway I70 (Miles 89-93)
Hyperspectral, 2006
(63 bands)
Multispectral, 2007
(4 bands)

32. Determine the best band for cut-leaved teasel
Normalized Difference : (G-T)/G
9000
8000 Teasel Grass Bare soil Tree
Relectance (x1000)
7000
11 24 31 41
6000
5000
4000
3000
2000
1000
0
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61
Blue Green Red Infrared
Bands

33. 6000
Teasel Bare Soil Grass Others
5000
Reflectance (x1000)
4000
3000
2000
1000
0
Blue Green Red Infrared
Bands

34. 2006 2007
2006 2007 Change
Teasel 8.5% 13% +4.5%
Grass 78.4% 74.5% -3.9
Bare Soil 11.8% 3.3%Grass death -8.5
Others 1.3% 7.8 +6.5

36. Percentage of Cut-leaved Teasel Control and Grass
Cover Visual in June 2007
Teasel Grass Cover
Treat Fall 2006 Spring 2007
Tall Canada
Rosette Seedlings
Fescue Wildrye
1 Triclopyr Triclopyr 16.3 C 31.3A 66.3 A 67.5 A
Metsulfuron-
2 Dicamba 73.8 B 66.3 A 80 A 84.8 A
methyl
3 Dicamba Dicamba 98.8 A 58.8 A 70 A 78.8 A
4 Aminopyralid Aminopyralid 100 A 63.8 A` 82 A 79.5 A
Metsulfuron- Metsulfuron-
5 92.5 B 40 A 67.5 A 65 A
methyl methyl
* Means within a column followed by the same letter are not statistical different. T test p>0.05

37. What do we know now?
 Plants emerge during 2 distinct periods in Missouri
 Teasel has two important peaks of above ground growth
 Teasel stores resources in the taproot to catapault plants into
reproduction
 Seed production is greatest when plants invade new areas;
seeds reach viability quickly following initial flowering
 Mowing below 12 cm precludes plant flowering; plants remain
alive and flower the following year
 Herbicides can reduce the number of existing plants
and imazapyr reduces the emergence
 Remote sensing can identify teasel; combination of herbicides
and seeding desirable grasses is most effective strategy

38. Chester McWhorter (USDA weed scientist)
“I have spent the last 16 years of my career
working on johnsongrass, and I can report that
johnsongrass is a bigger problem today than
when I began.”
-1991
I have worked on teasel for about 8 years and cannot
say populations are in decline!

39. Questions?
Questions