1. Purple Loosestrife State-wide Program
Missouri Department of Conservation
Invasive Plant Workshop
Powder Valley CA
Kirkwood , Missouri
May 16, 2012
Kyle Lairmore
Private Land Conservationist
Missouri Department of Conservation

2. What is Purple Loosestrife ?
(Lythrum salicaria)
•Native of Europe, Asia and portions of Africa and
Australia
•Introduced in the US as a landscaping plant due to
its showy purple blooms
•Invasive to wetlands throughout the mid-western
and northeastern United States.
•Produces 1-50 stems per plant with a height ranging
from 3-7 feet tall
•One plant can produce as much as 2.5 million seeds
annually which can remain viable in the soil for
many years.
•It often outcompetes native vegetation and
eventually creates a monoculture which affects the
natural community

3. Purple Loosestrife Distribution

4. Current Purple Loosestrife Program
 Program created in the late 1980’s
 4-6 hourly employees hired each summer
(June-July)
Control Methods:
 Chemical
 Biological

5. Chemical Control
 Important to choose
correct aquatic approved
herbicide and follow label
directions
 Proper application
technique and safety
precautions
 Sponge, spray, etc
 Protective clothing, etc.
 Herbicide – Rodeo + Surfactant

6. Biological Control
 Involves the release of a
specific species to
restrict the spread of the
invasive.
 Introductions must be
carefully studied and
monitored so as to not
cause another problem
 Examples include:
 Foliage eating beetles
(Galerucella spp.) and
root-boring weevils
(Hylobius spp.) for Purple
loosetrife

7. Comparison of Various Herbicides to
Improve Effectiveness of
Purple Loosestrife Control
MDC Project Leader: Kyle Lairmore (MDC
PLS)
Principal Investigator: Doreen Mengel (MDC
RS) & Kyle Lairmore (MDC PLS)
Team members: Ivan Vining, Brent
Vandeloecht, Ted Seiler, Bill White, Bob
DeWitt & John Knudsen (ALL MDC)

8. Study Need
Looking at alternative herbicides that
will have a residual effect on the plant
as well as prevent successful
germination by seeds in the soil
Reduce staff time and funding towards
program (long term)
Residual effect on purple loosestrife
with minimal effect on non-target plant
species

9. Herbicide Selection
 Rodeo (glyposate)  Renovate 3A (triclopyr)
 Habitat (imazaphyr)  Streamline
 Clearcast (imazamox) (aminocyclopyrachlor)
 Capstone (aminopyralid
+ triclopyr amine)

10. Management Prediction or Objective
 Determine which treatment provides the most
effective long-term population control of
purple loosestrife.
 Determine the effect of each treatment on the
native plant community.

11. Uncertainties/Risk Tolerance
 Is there an herbicide labeled for aquatic settings that
provides long-term control of purple loosestrife?
 What are the risks of not treating purple loosestrife
annually?
 What are the effects on the native plant community?

12. Evaluation of Success
 A herbicide will be considered successful if it meets the
objectives of the study; it shows a long-term effect on
purple loosestrife while having minimal if no effect on
native plant community and re-vegetation of desirable plant
species
 A herbicide would not be selected if it shows no long-term
effects on purple loosestrife and allows no re-vegetation of
native and/or desirable plant species

13. Summary
 Purple Loosestrife continues to be an issue in
wetlands, competing with native plants while not
providing any benefits to wildlife
 We have an active state-wide eradication program
 We hope the research project will help us find
alternative herbicides which will be more
effective for eradicating Purple Loosestrife

14. Questions?
Kyle Lairmore
Missouri Department of Conservation
573-437-3478 *112
Kyle.Lairmore@mdc.mo.gov