UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C
.. 20460 

### JUL 0 22015

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: BEAD Review ofDiquat Dibromide (032201) Use SummaryTables Submittedby Syngenta Crop Protection, DP#427305 

### FROM:

THRU:

TO: Cynthia Doucoure, Environmental Protection Specialist 

# C**~** Science and Information Analysis Branch Biological and Economic Analysis Division (7503P) Diann Sims, Chief

# ~ Science Information and Analysis Branch Biological and Economic Analysis Division (7503P) BonnieAdler, Chemical Review Manager Risk Management and Implementation Branch V Pesticide Re-evaluation Division (7508P)

This memorandumtransmits the review ofthe DiquatDibromideUse Summary Table (UST) submittedbySyngenta CropProtection. We evaluated the label information for accuracy and assessed the following variables to determine ifthe subset oflabels presented inthe report are representative oftheregistered use patterns: 1) Use Sites 2) Formulations 3) Methods 4) Max Application Rates and Number ofApplications 5) Limitations (i.e. MinimumRetreatment Interval, Preharvest Interval, etc.) & Restrictions Diquat dibromide cation is an herbicide used in agricultural, residential and commercial/industrial locations, as well as aquatic areas. Currently, there are 95 Section 3 registrations, including two technical registrations (100-1332 and 74530-57), and 24 Section 24 (c) diquat dibromide registrations. Syngenta submitted one DiquatDibromide UST with agricultural, non-agricultural, and aquatic label data in separatetabs
. The UST label data are Page 1of3based on a subset ofdiquat dibromide active registrations including 3 Section 3 registrations (100-1061, 100-1091, and 100-1390) and 8 24(c) registrations (FL000008, -9, and -10, PR030001, SC000005, WA040011, ID100006, and OR080025). Overall, the information provided inthe UST is representative ofmost ofdiquat dibromide uses. Syngentaprovides very detailed information that clearly describes the use patterns for most diquat dibromide use sites. However, BEAD found a few discrepancies as described below.


### I. Sites BEAD found that all use sites registered by Syngenta are represented inthe UST. The only discrepancy found was the identification ofartichoke, asparagus, and ginseng as bearing crops in the UST. These sites are identified as "non-bearing" in the referenced label (100-1061). BEAD also found that SourceDynamic, LLC, another registrant, has an end-use registration (82542-15) for use ofdiquat dibromide ontwo crops (avocado and elderberry) not found in Syngenta's UST.


### II. Formulations Diquat dibromide products are formulated as soluble concentrates, liquids ready-to-use, and oil-in-water emulsion. All Syngentaformulations are represented inthis UST except liquid ready-to-use (100-1180 and 100-1114) and oil-in-water emulsion (100-1331). 

### III. Application Methods Most ofthe diquat dibromide application methods are represented in the UST, including broadcast, spot, and directed sprays using ground and aerial boom sprayers, airboats, sprayhandgun, and backpacks. The onlymissing application type is stump treatment (100-1179 for example) and missing application equipment include hose-end sprayer (100-1344), tank sprayer (100-1179 for example) and otherhand-held sprayers such as pressure, pump-up, trigger sprayer (100-1329 and 100-1115 for example).


### IV. Max Application Rates and Number ofApplications The application rates inthe DiquatDibromide UST are presented for the active ingredient diquat cation, not the dibromide salt. Most ofthe minimum and maximum single application rates provided inthe UST for agricultural crops, non-agricultural use sites, and aquatic sites accurately reflects the application rates found onthe label. Foruse sites that contain missing use patterns (maximum number ofapplications, application rates per crop cycle, crops cycles per year, number ofapps peryear and yearly application rates), Syngentahas provided proposed values with yellow highlights in the UST. Page 2 of 3Syngenta's UST includes a spottreatment application rate for sites such as fence lines, farmyards, and barrier strips (0.5 lb a.i. per acres single max app rate) and a spot treatment dilution rate of0.01 lb a.i. per gal for landscape and commercial greenhouse use sites. However, BEAD also found on label 100-1344 a higher single maximum application rate of 10 fl oz per 350 sq

### ft, which converts to 0.97 lb a.i. per acre for several outdoor uses including landscape, patio, fencerows, etc.


### V. Limitations & 

### Restrictions All pertinent limitations and restrictions were found in the DiquatDi bromide UST.


### Conclusion: BEAD reviewed the UST from Syngenta CropProtection and found that it represents most ofthe diquat dibromide use patterns. Feedback from Syngenta onthe labeled "non-bearing" designation for artichoke, asparagus, and ginseng and onthe missing spot treatment application rate, formulations, and application methods are recommendedbefore finalizing the Syngenta UST for use in risk assessment.

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