1. Research and Technical Review
of Clearcast™ for Chinese Tallow Tree (Triadica sebifera) Control
Todd Horton
SePRO Corporation
Jack Whetstone
Clemson University

2. Clearcast research and EUP results
Clearcast was evaluated under an Experimental Use Permit (EUP) from
Included multiple university trials
Operational applications
Demonstration plots
Trials focused on submerged aquatic plants and wetland invasive and nuisance species
Federal registration (section 3 label) approved in March 2008
State registrations followed

3. Chinese tallow tree control
Highly invasive woody plant found in coastal states from North Carolina to Texas
Selective control in hardwoods is difficult
Requires individual plant treatment

4. Initial discovery
, Houma, LA: Clearcast at 0.5% was applied to mixed brush and hardwood species using a handgun delivering 50 gpa
Broadcast rate equivalent to 32 oz/A (0.25 lb ai/A)
Included 1% methylated seed oil (MSO)
Although limited woody plant activity was anticipated, a single Chinese tallow tree was highly affected
Other desirable woody plants, including water oak, were not injured

5. Tallow tree and water oak at application 4-19-06

6. Initial symptoms on tallow
June 26, 2006 (10 weeks after treatment)

7. Other trials indicated hardwood selectivity
Clearcast at 0.5%
MSO at 1%
25 days after treatment
Treated cattail and red maple

8. Other trials indicated hardwood selectivity
Clearcast at 0.5%
MSO at 1%
63 days after treatment
Cattail was controlled and red maple had minimal injury
These findings led to further studies

9. Tallow tree / Hardwood screening research and demonstration
LSU (Dearl Sanders) conducted a trial on sapling bald cypress (2006)
Additional hardwood selectivity trial ongoing (2008)
Numerous EUP applications in LA to further compile information on selectivity and control
Lafayette, Hayes, Montgomery, Shreveport, Cade
Aerial application trial with Clearcast in southeast Texas
Cooperators include NRCS, BASF, ChemAir
Aerial application trial with Clearcast in South Carolina
Cooperators included TNC, SC DNR, Clemson University, BASF

10. Cypress Screening (LSU Sanders)
Study conducted by Dr. Dearl Sanders at Louisiana State University shows the tolerance of foliar applied Clearcast to cypress seedlings from rates ranging from 64oz/A to 4oz/A. 64 32 24 16 8 4
Clearcast rate (oz/A)

11. LSU Study: Sapling cypress leaf browning
(non-treated)
Clearcast (oz/A)

12. LSU Study: Sapling cypress leaf browning
Typical use rates necessary for Chinese tallow tree control (32-64 oz/A) did not result in bald cypress mortality
Saplings would likely have the greatest susceptibility to herbicide injury
Some leaf burning and browning was observed on saplings
Symptoms peaked at 83 days after treatment, then subsided
Additional field trials with Clearcast have documented bald cypress selectivity/safety
Tested a wide range of size and age of cypress

13. Tallow tree / Hardwood screening Lafayette, LA
Clearcast at 0.5% + 1% MSO
- Handgun app.
45 days after treatment
Control of Chinese tallow tree in sensitive sites

14. Tallow tree / Hardwood screening Lafayette, LA
Clearcast at 64 oz/A + 32 oz /A MSO
- Handgun app.
6 Months after treatment
Selective control of Chinese tallow tree in ditches and drainages

15. Symptoms from Clearcast on Chinese tallow tree
Untreated
Clearcast 64 oz/A
(note cambium death)
Arsenal Powerline
(terrestrial herbicide)
Symptoms from Clearcast on Chinese tallow tree
(6 Months after treatment)

16. Tallow tree / Hardwood screening Hayes, LA
Clearcast at 0.5% (equivalent to 32 oz/A) + 1% crop oil
- handgun
Selective control of Chinese tallow tree in a wetland site with cypress, oak, and maple
10 Months after treatment
Treated cypress tree
(sprayed to wet)

17. Tallow tree / Hardwood screening Hayes, LA
Clearcast at 0.5% (equivalent to 32 oz/A) + 1% crop oil
Selective control of Chinese tallow tree growing amongst cypress
10 Months after treatment
Treated both tallow and cypress trees

18. Tallow tree / Hardwood screening Hayes, LA
Clearcast at 0.5% (equivalent to 32 oz/A) + 1% crop oil
Tallow tree controlled
Adjacent oaks not damaged
Note: handgun reached only lower 1/3 to ½ of tree
10 Months after treatment
Treated tallow tree

19. Tallow tree / Hardwood screening Hayes, LA
Clearcast at 0.5% (equivalent to 32 oz/A) + 1% crop oil
Tallow tree growing under and amongst cypress and maple
Willows were controlled or severely injured
10 Months after treatment
maple
Cypress tree
Treated tallow tree

20. Aerial (helicopter) trial in East Texas
Wetland reserve program area near Liberty, TX
2, 5-acre sites applied via helicopter at 15 gpa
Site 1: Clearcast at 48 oz/A + MSO at 32 oz/A
Contained a 9-year old planting of (10-20’) bald cypress, nutall oak, willow oak, and water oak
Moderate infestation of Chinese tallow tree
Site 2: Clearcast at 64 oz/A + MSO at 32 oz/A
Uneven aged stand of mixed hardwoods with a moderate to severe infestation of tallow trees from 10’ in the understory up to 50’ in the canopy
Canopy of 50-80’ hardwoods (oak, maple, elm, ash)

21. Aerial Clearcast results in Liberty, TX (site 1)
Clearcast at 48 oz/A
Excellent selectivity on oak and cypress
Some leaf yellowing noticed on willow oak
Leaf burn noticed during application year on cypress
Full recovery 10 MAT
Control of tallow estimated at 90% 10 MAT with additional mortality anticipated

22. Aerial Clearcast results in Liberty, TX (site 1, 48 oz/A)
Clearcast at 48 oz/A
Excellent selectivity on oak and cypress
Controlled estimated at 90% 10 months after treatment with additional mortality anticipated
tallow tree
willow and water oak

23. Aerial Clearcast results in Liberty, TX (site 1, 48 oz/A)
tallow tree
nutall oak

24. Aerial Clearcast results in Liberty, TX (site 1)
Clearcast at 48 oz/A
Other hardwoods with minimal impact included sweetgum, red maple, green ash, and wax myrtle
Minimal impact on herbaceous species 10 MAT
Injury noted on hawthorn and Baccharis

25. Aerial Clearcast results in Liberty, TX (site 2)
Clearcast at 64 oz/A
Excellent hardwood safety
10 months after treatment: Control of tallow estimated at 75-85% for plants that ranged from 10-50’ tall and received some coverage
Limited coverage and shadowing affected control in the understory

26. Aerial Clearcast results in Liberty, TX (site 2, 64 oz/A)

27. Aerial Clearcast results in Liberty, TX (site 2, 64 oz/A)

28. 48 oz Imazapyr
64 oz
Imazapyr
96 oz Glyphosate

29. Aerial (helicopter) trial in South Carolina
June 2006, helicopter application at 10 gpa
Treated with Clearcast at 64 oz/A + 1% MSO
Site had a mixed stand of hardwoods and Chinese tallow tree
Also targeted phragmites

30. Selective Tallow and Phragmites (1 year after treatment)

31. Clearcast – Chinese Tallow
32 Oz. Clearcast + 1% MSO in 15 Gallons
10 August 2006
11 DAT

32. Summary of research on brush and tallow tree control
32-64 oz/A Clearcast has controlled Chinese tallow tree in numerous trials and demonstration plots
Higher rates are necessary for severe infestations and mature stands
Lower rates may suffice for small tallow trees and will provide greater safety for small hardwoods
Similar results have been observed with ground/handgun applications and aerial helicopter applications
Application method and volume should provide adequate foliar coverage of crown and terminal shoots
10-15 GPA aerial
50 GPA handgun
20-50 GPA broadcast ground
MSO at 1% or 32 oz/A used in all trials to date

33. Summary of research on brush and tallow tree control
Majority of established hardwoods (>2” dbh) in these trials have exhibited very good tolerance to Clearcast at oz/A
Oak (live, nutall, water, willow) – Sugarberry
Bald cypress – Southern Red Cedar
Red maple – Groundsel-tree (Baccharis)
Hickory – Elm
Red Mulberry – Hackberry
Wax Myrtle – Green ash
Pecan
Loblolly Pine
Injury is possible on stressed plants and smaller trees
Willow, black cherry, hawthorn, sweetgum and sumac are among the sensitive/susceptible woody species
Sweetgum may be controlled at higher volumes, smaller trees

34. Additional Information
Clearcast has a full aquatic label with no fishing, swimming, or livestock watering restrictions
Label also allows for applications in noncropland and riparian areas
The active ingredient in Clearcast received an exemption from tolerance designation from the US EPA
Thus, Clearcast has limited irrigation restrictions (50 ppb) and…
University trials have illustrated safety to turf, corn, cotton and rice at rates below 50 ppb

35. Additional Information
Clearcast also has activity on a wide range of nuisance and invasive aquatic weeds including:
Alligatorweed – Common salvinia
Pennywort – Frogsbit
Phragmites – Cattail
Water lettuce – Water hyacinth
Pondweeds

36. Acknowledgements Dearl Sanders, LSU
Barton Joffrion, Terra Bonne Extension
Mitch Samaha, LDWF
Tom Smith, USDA-NRCS
Jack Whetstone, Clemson
Red River, Chemair
C3M, Summit Helicopters

37. SePRO Contact Information
For tallow control and other
pond management problems
Todd Horton