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

### MAY 14 

## 2012

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: FROM: BEAD Chemical Profile for Registration Review: Dazomet (035602) Leonard Yourman, Plant Pathologist

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THRU: Biological Analysis Branch .- { 1. Sepehr

### Haddad, Environmental Protection Specialist

# /tr.J'**~** Science Information and Analysis Branch 

## I
DerekBerwald, Economist 

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# 1J./\..\fS Economic Analysis Branch 

# UJ Biological and Economic Ana sis Division (7503P) Arnet Jones, Chief Biological Analysis Br c Diann Sims, Chief 

# A**·1Z 1L.~<.¥-""'"**  Science Information and Analysis Branch Timothy Kiely, Chief

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# 0 Economic Analysis Branch

# ~ Biological and Economic Analy is Division (7503P) TO: Dana Friedman, Chemical Review Manager Risk Management and Implementation Branch 2 Pesticide Re-evaluation Division (7508P)

Product Review Panel date: May 2,2012

INTRODUCTION The purpose ofthis document is to convey usage information and a broad overview ofthe pest management roles ofpesticides that are beginning to undergo registration review. The anticipated audience consists ofthe team ofEPA staffcurrently evaluating the registration status ofdazomet, and eventually the general public. This document builds upon the data alreadyprovided inthe "Usage and Label Use DataPackages" that are also provided to Registration Reviewteams by BEAD. The document is based on information and data available to BEAD as ofApril, 2012. Dazomet [Basamid®] is a non-selective soil fumigant with fungicidal, herbicidal and nematicidal properties (RED-FS, 2008). Soil fumigants form gasses when applied to soil. Once in the soil, the fumigants work by controlling pests that can disrupt plant growth and crop production. When dazomet is applied, itis quickly broken down into several degradates; the major degradate being methyl isothiocyanate (MITC). MITC is highly volatile and is responsible for the fumigant properties ofdazomet. Dazomet is used on a wide range ofsites including golfgreens ortees, nonbearing crops, turfsites, ornamental sites, field nurseries, compostpiles, potting soils, and strawberries and tomatoes (in California only). Under moderate soil temperature and moisture, dazomethas been successful in replacing such former methyl bromide-uses as turfgrass removal for golfcourses that were undergoing renovation (e.g., Brecke et al., 2005). Dazometuses that have successfully replaced methyl bromide can be considered to have high benefits.
COMMON FORMULATIONS AND APPLICATION METHODS Generally, dazomet uses fall into two basic categories, soil fumigation or antimicrobial use. For soil fumigation, the formulation is granular, and for the antimicrobial use the formulation is pelletedltableted, liquid (soluble concentrate and flowable concentrate) solutions, water soluble packaged solids, and ready to use solutions.


### USE SITES Dazometis labeled for both agricultural and non-agricultural uses. There are no residential uses ofdazomet. Dazomet was first registered inthe United States in 1967 as an algaecide, a bacteriostat, and a microbiocide in a variety ofcommercial and industrial applications such as pulp and paper mills, cooling tower waters, and non-food adhesives. In the late 1980s pre-plant soil uses ofdazomet were registered. Unlike other soil fumigants, dazomet is applied as a dry granule and incorporated into the soil or applied to the soil surface and watered into the soil to activate it (US EPA, 2009). Agricultural Use Sites Agricultural sites are for soils ofnonbearing fruit and nuttrees. It is also labeled for use on soils for strawberries and tomatoes only in California. Non-Agricultural Use Sites Dazomet is labeled as a soil fumigant on the following sites: golfgreens and tees, sites, turfsites, ornamental sites, field-grown plant nurseries, compostpiles, and potting soils. Itis used

2primarily to manage weeds (including golfcourse renovations requiring killing ofexisting turfgrass), nematodes, and pathogens priorto planting ofthe crops. Non-agricultural antimicrobial use sites for which dazomet is labeled include: 1) as a treatment during the production ofpulp and paper; 2) as a material preservative treatment for paper coatings, non-food adhesives, epoxy flooring compounds, slurries, and high viscous suspensions; 3) as a biocide treatment used during petroleum operations; 4) as a biocide treatment to recirculating cooling water systems; and 5) as a remedial woodtreatment to utility poles (REDFS, 2008). Italso appears to have uses on rights-of-way.


### USAGE Agricultural Use A review ofavailable proprietary data did not yield information onthe amount ofdazomet used for agricultural uses. The onlypublic data source which had information on agricultural use of dazomet was from the state ofCalifornia which showedthat approximately 800 lbs a.i. of dazomet was used on soils for plums in 2009, and approximately 600 lbs a.i. was used on soils for plums in 2010. In spite ofa label for pre-plant use for strawberries and tomatoes, BEAD found no data onusage for these sites. Non-Agricultural Use Interms ofnon-agricultural use, information is available for dazomet use on golfcourses in 2002 (15,500 lbs. a.i.) and 2006 (approximately 6,000 lbs. a.i.), and by lawn care operators (approximately 3,500 lbs. a.i.) in 2006 (Kline & Co. 2002,2006). Additionally, according to the Nursery and Floriculture Summary ofthe USDA, approximately 15,000 pounds ofdazomet was used as a soil fumigant in 2003 (USDA-NASS, 2004). Also, in 2010 in California, 55,511 pounds ofdazomet were used onrights-of-way; however, there was no information available on use ofdazomet for rights-of-ways in other states (CDPR, 2010).


### PREVIOUS BEAD ASSESSMENTS FORDAZOMET Most ofthe BEAD work on dazomet has been in the context ofbenefits assessments or impact assessments for other fumigants including methyl bromide and 1,3-D, for which dazomet could be an alternative. In that context, dazomet was found to have lowbenefits relative to other fumigants inmany crops, due to inconsistent results, and less control ofweeds than other fumigants. However, where the availability ofother fumigants is restricted, dazomet could be an important alternative, along withthe otherMITC generators (Zinn and Smearman, 2007; Yourman and Smearman, 2007a; Faulkner and Yourman, 2007; Yourman and Smearman, 2007b).

3A report onuse ofdazomet in California indicates primary use sites in landscape and rights of way (Carter, 2008). This suggests some degree ofbenefits ofdazomet for those uses, probably because ofease ofapplication inthe granular fonnat.

BIOLOGICAL ASPECTS RELEVANT TO DAZOMET Dazomet is applied as a dry granule and incorporated into the soil or applied to the soil surface and watered into the soil to activate it (RED-FS, 2008). The ease ofapplication and efficacy for many use sites suggest a relatively highbenefit, especially with the need for alternatives after the phase-out ofmethyl bromide. Under moderate soil temperatures and moisture, dazomet has been successful 

### inreplacing such fonner methyl bromide-uses as turfgrass removal for golfcourses undergoing renovation (e.g., Brecke et al., 2005). Dazomet has been used in forest seedling nurseries, especially inwestern and northern states. Itgenerally has not provided comparable weed control compared to the long-time standard methyl bromide and its use has been found in some cases to a reduction in seedling grade (Fraedrich and Dwinell, 2003). This is possibly a consequence ofa low vapor pressure ofthe MITC component, which reduces the fumigant's dispersal within the soil especially under extreme soil moisture and temperatures (where methyl bromide might have been effective).

REFERENCES Brecke, B. J., Unruh, J. B., and Stephenson, D. 0.2005. Dazometblended with rootzone mix for fumigation. International Turfgrass Society Research Journal 10:1176-1178. http://archive.lib.msu.edultic/its/articles/2005jou1176.pdf Carter, J. 2008. Usage Report in Support of Registration Review for thefumigant Dazomet (035602), BEAD, January 15,2008. CDPR (California Department ofPesticide Regulation). Summary ofPesticide Use Report Data, 201 D-Indexedby Chemical. http://www.cdpr.ca.gov/docs/ pur /pur10rep/chmrptlO.pdf Faulkner, J. and Yourman, L.2007. Assessmentof the Benefits Soil Fumigants (Methyl Bromide, Chloropicrin, Metam-Sodium, Dazomet) Used by Forest Tree SeedlingNurseries, BEAD, April 20,2007. Fraedrich, S. W. and Dwinell, L. D. 200J. An evaluation ofdazomet incorporation methods on soilborne organisms and pine seedling production in southern nurseries. Southern Journal of Applied Forestry 27:41-51. http://www.srs.fs.usda.gov/pubs/ja/ja fraedrich003.pdf Kline & Co., 2002, 2006 RED-FS. 2008. Registration Eligibility Decision Fact Sheet: Dazomet. U.S. Environmental Protection Agency Office ofPesticide Programs. July 10,2008. http://www.epa.gov /oppsrrd1 /REDs/factsheets/dazomet

-fs.pdf

4USDA-NASS. 2004. Agricultural Chemical Usage 2003 Nursery and Floriculture Summary, September 2004. http://usda.mannlib.comell.edulMannUsdaiviewDocumentlnfo.do?documentlD=1 001 US EPA. 2009. Amended Reregistration Eligibility Decision for Dazomet. Yourman, L. and Smearman,S. 2007a.Assessment of the Benefits of SoilFumigation with Methyl Bromide, Chloropicrin, Dazomet, andMetam Sodiumfor Use in RaspberryNurseries, Fruit and NutDeciduous Tree Nurseries, andRose Bush Nurseries in California, BEAD, April 20, 2007. Yourman, L. and Smearman,S. 2007b. Chloropicrin, Methyl Bromide, Metam-sodium and Dazomet Use in StrawberryNursery Runner Production, BEAD, April 19, 2007. Zinn, N. and Smearman, S. 2007.Assessment of the Benefits of Soil Fumigation with Chloropicrin, Methyl Bromide, Metam Sodium andDazomet in OrnamentalProduction, BEAD, April 20, 2007

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