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Clearcast® herbicide, a new product from BASF Professional
Vegetation Management (ProVM), provides aquatic and terrestrial
weed control with minimal irrigation restrictions.
Clearcast is highly selective – controlling target weeds, leaving
desirables unaffected, making it ideal for aquatic areas used for fishing
and other recreation activities.
• Clearcast is part of the imidazolinone family of chemistry; discovered in 1969.
• Imazamox, the active ingredient in Clearcast, was first approved for use in 1997 on soybeans and is currently used on 15 different crops on a global basis.
• In 2003 imazamox received an exemption from tolerance designation from the US EPA, resulting in the waiving of food residue tolerance requirements for all potential food or feed uses of imazamox. It is the only organic herbicide that is exempt from all tolerances.
• BASF has conducted its aquatic research in conjunction with University Cooperators, US Army Corp of Engineers and consultants.
• Excellent results have been achieved with foliar treatments on floating and emergent species.
History and Development
• Clearcast is a liquid (water based) formulation containing 1.0 pound of active ingredient per gallon of product
• Clearcast does not contain a surfactant
• Foliar applications require the addition of an appropriate adjuvant for aquatic sites
• Clearcast is non-volatile and does not contain any petroleum solvents
Clearcast Herbicide Formulation
• No restrictions on fishing, swimming, drinking, and no live stock watering restriction
• No irrigation restrictions when residues fall below 50 ppb
• Labeled for use on golf course irrigation ponds*
* See label for specific irrigation restrictions
Clearcast Application Flexibility
• DO NOT use any Clearcast-treated waters from still or quiescent sources for irrigation purposes less than 24 hours after Clearcast application is completed.
• Waters receiving Clearcast either as a water treatment or as a foliar treatment on emergent/floating plants may be used for irrigation as long as concentrations are ≤ 50 ppb.
Irrigation Restrictions
• Still and quiescent waters with an average depth of four (4) or more feet receiving a foliar application of Clearcast (≤ 2 quarts per acre) to emergent/floating vegetation may be used for irrigation on allowable sites 24 hours after application is completed.
• There are no irrigation restrictions on allowable sites for the use of treated water from flowing waters, such as irrigation canals with an average depth of four (4) or more feet, receiving a foliar application of Clearcast (≤ 2 quarts per acre) to emergent/floating vegetation.
Clearcast Application Tips
• Good coverage is important for optimal control
• Surfactant is always required for emergent and floating species
• For best results, use a MSO or MSO/silicone blend
• Applications can be made around desirable hardwood vegetation
• The following types of spray adjuvants are recommended for use with Clearcast for emergent treatments:
Non-ionic
Modified seed oil
Vegetable oil concentrates
Silicone based surfactants
Invert emulsions
• Always use an adjuvant that is appropriate for aquatic use
Spray Adjuvants
• Clearcast inhibits a plant specific enzyme (AHAS) that is essential to the production of three amino acids.
• Sensitive plants stop growing within 24 hours after treatment and then slowly senesce as food and energy reserves are exhausted. Speed of senescence will vary with plant size and growth habit.
• Clearcast is quickly absorbed by plant foliage and translocated throughout the plant where it concentrates in the actively growing portions of roots and shoots. This characteristic enhances the long term control of many perennial plant species.
• For foliar applications Clearcast is rainfast within one hour.
• Clearcast is taken up by plant roots in terrestrial settings. Root uptake in aquatic settings is likely to be less significant because of the significant water solubility.
Mode of Action
• Clearcast herbicide has a very favorable toxicological profile and product labeling carries a CAUTION signal word
• Acute mammalian (human) toxicity via oral, dermal, eye and inhalation routes of entry are all EPA category III-IV, the lowest level of concern
• Based on the results of EPA required testing, Clearcast is not expected to cause any adverse chronic affects in mammals
• Clearcast is not a carcinogen, terratogen, mutagen nor is it an endocrine disruptor
Mammalian Toxicology
• Clearcast has a very favorable ecotoxicology profile
• Based on the battery of studies performed to achieve EPA registration, Clearcast is not expected to have an adverse acute or chronic effect on birds, fish, mammals, insects, mollusks or crustaceans
Ecotoxicology
Species/Test LC50/LD50 NOEC/NOEL
Mallard duck
8-day dietary >5572 ppm 5572 ppm
14-day dietary >1950 mg/kg 1950 mg/kg
Bobwhite quail
8-day dietary >5572 ppm 5572 ppm
14-day dietary >1846 mg/kg 1846 mg/kg
Honey bee contact >25 mg/bee 25 mg/bee
Ecotoxicology
Species/Test LC50 NOECBluegill sunfish
96h flow-through >119 ppm 119 ppm
Rainbow trout
96h flow-through >122 ppm 122 ppm
Daphnia
96h flow-through
122 ppm>122 ppm
Water:
• The primary means of dissipation in water is via dilution and photolytic breakdown
• Photolytic breakdown in water results in a 10 to 14 day half life
• Photolytic half life will vary based on water clarity, depth, vegetative cover and light intensity
• Clearcast herbicide does not bioaccumulate in aquatic organisms
Environmental Fate- Water and Sediment/Soil
Sediment/Soil:
• Clearcast herbicide does not partition into or accumulate in the hydrosoil/sediment
• Under aerobic soil conditions (terrestrial), Clearcast is degraded by soil microorganisms
• The half life of Clearcast in soil is approximately 12-days, depending on environmental and soil conditions
•Water hyacinth•Frogbit•Water shield•Water lily•Alligator weed•Primrose•Common salvinia•Lotus•Parrotfeather•Water four leaf clover
•Pennywort•Pickerelweed•Smartweed•Spatterdock•Sagittaria•Cattail•Phragmites•Giant reed- arundo•Chinese tallowtree•Brazilian pepper tree
Floating, emergent, and shoreline weeds and brush
Shoreline
Control
Purple Loosestrife9 months after treatment – 32 oz/A
Cattail 9 months after treatment - 32 oz/A
Cattail control 1 year after treatment - 32 oz/A
Cattail control 30 days after treatment - 32 oz/A
Phragmites Control1 year after treatment - 64oz/A + 1% MSO
Arundo 0.5% + 1% MSO9 months after treatment
Selective Chinese Tallowtree and Phragmites ControlAerial application of Clearcast applied over the top of desirable hardwoods.
Selective Chinese Tallowtree Control
Trees shown to be tolerant to Clearcast
• Red Mulberry - Morus rubra
• Salt bush, Groundsel-tree – Baccharis halimifolia
• Wax Myrtle – Myrica cerifera
• Loblolly Pine - Pinus taeda
• Southern Red Cedar - Juniperus silicicola
• Sugarberry - Celtis laevigata
• Bald Cypress - Taxodium distichum
• Elm Species – Ulmus spp.
• Chinaberry tree - Melia azedarach
• Black Willow - Salix nigra
• Live Oak - Quercus virginiana
Species listed are results from research conducted by Jack Whetstone, Clemson University
6464 3232 2424 1616 88 44 00
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.
Floating and EmergentWeeds
Untreated Clearcast 16oz/A
Water Hyacinth6 weeks after treatment
Water Hyacinth4 weeks after treatment
Cattail, Sedge and Alligatorweed 25 days after treatment - 0.5% v/vRed maple tolerance at 64oz/A
Cattail, Sedge and Alligatorweed 63 days after treatment - 0.5% v/v
Watershield Before Treatment
Watershield 6 weeks after treatment - 64oz/A
Good Coverage is Critical - surfactant needed
Spatterdock, Watershield and Waterlily - 64 oz/A
Waterlily, Spatterdock and Watershield 6 weeks after treatment
Common Salvinia in Louisiana64 oz/A + MSO/silicone blend 1% v/v
Clearcast Symptoms
Common Salvinia in Louisiana6 month after treatment
Frogbit, Cattail and Pickerelweed Control 2 months after treatment - 32oz/A
American Pondweed25 days after treatment
• Slow acting so no dissolved oxygen concerns
• Only EPA tolerance exempt herbicide
• Labeled for golf course waters
• More consistent control compared to glyphosate alone
• Great tank mix partner with glyphosate
• Good coverage is important for optimal control
• Surfactant is always required for emergent and floating species
• For best results, use a MSO or MSO/silicone blend
• Applications can be made around desirable hardwood vegetation
• Non volatile
Summary
What is the difference between Clearcast and Habitat® herbicide?
• Clearcast is approved for both submerged and foliar applications.
• Clearcast is more selective.
• Clearcast has minimal effect on brush.
• Clearcast can be used in irrigation water with minimal irrigation limitations.
• Clearcast has a short soil residual.
Questions
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