UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D

.C

., 20460 

## MAY 

## 21 2015

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM SUBJECT: 

### Non-Agricultural Use & 

### Usage Report for the Herbicide Isoxaben (PC Code # 125851}in Support ofRisk Mitigation & 

### Preliminary Interim Decision FROM:

THRU:

TO:



### Summary 

### Liabeth Yohannes, Biologist Science and Information Analysis Branch Biological and Economic Analysis Division (7503P) Steve Jarboe, Team Leader

## A..7~ Science Information and

## ~**B;~cif'** Biological and Economic Analysis Division (7503P) Christina Scheltema, Chemical Review Manager Risk Management and Implementation Branch Pesticide Reevaluation Division (7508P)

Isoxaben is undergoing registrationreview bythe Pesticide Reevaluation Division (PRD). The Biological and Economic Analysis Division (BEAD) conducted an analysis ofisoxaben's nonagricultural usage and labeled maximum applicationrates for non-agricultural uses in support of risk mitigation and preliminary interim decision. lsoxaben (PC Code 125851) is a soil-applied pre-emergent herbicide used for control ofbroadleafweeds. Based on datapresented in this document, isoxaben usage makes up a small fraction ofherbicides used in the professional turf, ornamental and consumermarkets and has a maximum single application rate of 1.0 lb a.i./acre. Background 

### The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) authorizes EPAto register pesticides under40 Code ofFederal Regulations (CFR) Part 158. FIFRA requires the EPA to regulate the use ofa pesticide to the extent necessary to prevent unreasonable adverse effects on the environment, including human health, where 'unreasonable' is defined as taking into account the economic, social, and environmental costs and benefits ofthe use ofthe pesticide.Isoxaben is registered for use on a variety ofnon-agricultural sites including turf grass, ornamentals (landscape, container and field), groundcovers/perennials, conifer plantations/hardwood nurseries, non-bearing fruit and nut trees, non-bearing vineyards, and other non-cropland. Itis also registered for agricultural use on bearing fruit and nuttrees, vineyards, and eucalyptus. The primary risk concern for isoxaben is to non-targetterrestrial plants, primarily from spray driftresulting from broadcast applications. 

### Non-Agricultural Usage In the professional turfand ornamental market (e.g., golfcourses, horticultural nurseries, landscape contractors), isoxaben makes up a small fraction ofthe herbicides used in each sector (Table 1; Kline and Co., Inc., 2006, 2009, and 2011). In 2011, isoxabenusage was approximately 2% ofall herbicides applied (an estimated total of50,000 lbs a.i.) in the 

### turfand ornamental marketwith the largestuses reported for horticultural nurseries ( < 1 % oftotal; 28,000 lbs a.i.), golfcourses (<0.3% oftotal; 9,000 lbs a.i.) and institutional turf(< 0.6% oftotal; 7,000 lbs a.i.). Less usage ofisoxaben was reported inthe landscape contractor and lawn care operator sectors in 2011 (3,000 lbs a.i. applied in each sector, respectively). From 2006 to 2011, isoxaben usage by golfcourses and horticultural nurseries increased, while usage by landscape contractors decreased. In the consumermarket (e.g., lawns and gardens), isoxabenusage made up less than 4% oftotal herbicide usage on lawns. Less than 223,000 lbs a.i. were applied in 2011 and less than 139,000 lbs a.i. were applied in 2009. 

### Table 

### 1. Non-Agricultural Usage ofIsoxaben in

### Professional Turf& 

### Ornamental and Consumer Markets by Sector (2006, 2009, 

### and 2011) 

### Year Site/Sector Lbs A.I. % 

### ofTotal (data) (Thousand)

2011 GolfCourses 9 0.3 2006 GolfCourses 2 0.3 2011 Horticultural Nurseries 28 0.9 2006 Horticultural Nurseries 21 1 2011 Institutional Turf 7 0.6 2006 Institutional Turf No usage reported No usage reported 2011 Landscape Contractors 3 0.3 2006 Landscape Contractors 7 2.3 2011 Lawn Care Operators 3 0.04 2011 Consumer lawn <223 <4.2 2009 Consumer lawn < 139 <3.6 Source: Kline and Co., Inc
., 2006, 2009, and 2011

### Maximum Single Application Rates on Isoxaben Labels for Non-Agricultural Uses Themaximum single applicationrate on nonagricultural sites, including turf, landscape ornamentals, field grown ornamentals, groundcovers/perennials, and home lawns ranges from 0.5 - 1 lb a.i./acre. These data are based onregistered labeled uses ofisoxaben.


### References Kline and Co., Inc., 2006, 2009, and 2011.