MDAR/MassDEP 1 June 2013 -reposted here 2014
CLIPPER® HERBICIDE PRODUCT EVALUATION AND
RECOMMENDATION
(June 2013)
MDAR/MassDEP 2 June 2013
This document is a review of the aquatic herbicide Clipper® (EPA. Reg. No. 59639-161; Valent
Biosciences Corp.). It contains product-specific aspects related to use characterization, inert
formulation ingredients and adjuvants, and toxicity and effects of these ingredients to human
health and non-target organisms. This document complements the MDAR/MassDEP review of
the active ingredient flumioxazin (MDAR/MassDEP 2013).
1. Product Formulation
The product label indicates that the Clipper Herbicide is formulated as water dispersible granules
containing 51% flumioxazin by mass (Valent Corp., 2012). The MSDS document indicates that
the formulation also contains kaolin clay as a carrier at approximately 16% by mass. The identity
of the other ingredients (also referred to as inerts) in Clipper Herbicide is considered proprietary;
therefore, the manufacturer does not identify the other ingredients on the general or supplemental
product labels or material safety data sheets (MSDS).
Proprietary information on the other formulation ingredients was obtained through a request for a
Confidential Statement of Formula. The proprietary ingredients were evaluated as part of this
review, but cannot be disclosed here for reasons of confidentiality.
The product label indicates that treatment of emergent vegetation requires the addition of spray
adjuvants to the tank mix. As directed on the label, only adjuvants labeled for aquatic use should
be utilized. Specific recommendations for adjuvants include those that contain non-ionic
surfactants.
2 Use Characterization
2.1. Use Sites
The product label for the flumioxazin-formulated Clipper Herbicide specifies that this product
may be applied for the control of vegetation in aquatic sites. Clipper Herbicide provides control
of various submerged, emergent, and floating aquatic plants. The product may be applied directly
to the water where there is limited or no outflow, including wetlands, lakes, fresh water ponds
and reservoirs (Valent Corp., 2012).
2.2. Application Methods
Clipper Herbicide is applied as a water-based solution having a pH of 5 to 7. If treating floating
or emerged weeds the addition of an adjuvant to the tank mix is needed. The product may be
broadcast applied to the water surface or injected below the water surface. The label suggests
that early morning applications may enhance weed control. The product may be applied by
backpack or handgun sprayer, airboat, helicopter, airplane or other application equipment that is
MDAR/MassDEP 3 June 2013
capable of thorough coverage of target plant foliage. Subsurface application may be done using
weighted trailing hoses to ensure the release of the herbicide under the surface and throughout
the biomass of aquatic vegetation. In situations where aquatic vegetation is dense, the label
suggests that up to half of the water body be treated at a time to avoid a rapid decrease in
dissolved oxygen caused by vegetation breakdown. It also notes that the remaining area of the
water body can be treated 10 to 14 days later.