Transcript Clearcast Herbicide for Control of Tallowtree Todd Horton

Research and Technical Review
of Clearcast™ for Chinese Tallow Tree
(Triadica sebifera) Control
Todd Horton
SePRO Corporation
Jack Whetstone
Clemson University
Clearcast research and EUP results
• Clearcast was evaluated under an Experimental Use
Permit (EUP) from 2005-2007
– 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
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
Initial discovery
• 4-19-06, 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
Tallow tree and water oak
at application 4-19-06
Initial symptoms on tallow
June 26, 2006 (10 weeks after treatment)
Other trials
indicated hardwood
selectivity
• Clearcast at 0.5%
– MSO at 1%
• 25 days after treatment
• Treated cattail and red
maple
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
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
Cypress Screening (LSU Sanders)
64
32
24
16
8
Clearcast rate (oz/A)
4
0
(%) browning
LSU Study:
Sapling cypress leaf browning
(non-treated)
Clearcast (oz/A)
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
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
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
Untreated
Clearcast 64 oz/A
(note cambium death)
Arsenal Powerline
(terrestrial herbicide)
Symptoms from Clearcast on Chinese tallow tree
(6 Months after treatment)
Tallow tree / Hardwood screening
Hayes, LA
• Clearcast at 0.5%
(equivalent to 32 oz/A)
+ 1% crop oil
- handgun
Treated cypress tree
(sprayed to wet)
• Selective control of
Chinese tallow tree in
a wetland site with
cypress, oak, and
maple
• 10 Months after
treatment
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
Tallow tree / Hardwood screening
Hayes, LA
Treated tallow tree
• 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
Tallow tree / Hardwood screening
Hayes, LA
maple
Cypress tree
Treated tallow tree
• 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
Aerial (helicopter) trial in East Texas
• Wetland reserve program area near Liberty, TX
• 2, 5-acre sites applied 6-25-07 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)
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
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
Aerial Clearcast results in Liberty, TX
(site 1, 48 oz/A)
tallow tree
nutall oak
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
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
Aerial Clearcast results in Liberty, TX
(site 2, 64 oz/A)
Aerial Clearcast results in Liberty, TX
(site 2, 64 oz/A)
48 oz
Imazapyr
64 oz
Imazapyr
96 oz
Glyphosate
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
Selective Tallow and Phragmites
(1 year after treatment)
Clearcast – Chinese Tallow
• 32 Oz. Clearcast + 1% MSO in 15 Gallons
• 10 August 2006
• 11 DAT
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
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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
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 32-64 oz/A
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Oak (live, nutall, water, willow)
Bald cypress
Red maple
Hickory
Red Mulberry
Wax Myrtle
Pecan
Loblolly Pine
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Sugarberry
Southern Red Cedar
Groundsel-tree (Baccharis)
Elm
Hackberry
Green ash
• 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
Additional Information
•
Clearcast has a full aquatic label with no fishing,
swimming, or livestock watering restrictions
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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
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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
Additional Information
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Clearcast also has activity on a wide range of
nuisance and invasive aquatic weeds including:
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Alligatorweed
– Common salvinia
Pennywort
– Frogsbit
Phragmites
– Cattail
Water lettuce
– Water hyacinth
Pondweeds
Acknowledgements
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Dearl Sanders, LSU
Barton Joffrion, Terra Bonne Extension
Mitch Samaha, LDWF
Tom Smith, USDA-NRCS
Jack Whetstone, Clemson
Red River, Chemair
C3M, Summit Helicopters
SePRO Contact Information
For tallow control and other
pond management problems
Todd Horton
864-270-5292
[email protected]