UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

'JUN i 4: 2011 

MEMORANDUM 

SUBJECT: Typical Use Data for Chlorpyrifos 

OFFICE OF 

CHEMICAL SAFETY AND POLLUTION 

PREVENTION 

FROM: Jonathan 

Biological 

Becker, 

Analysis 

Ph.D., 

Branch

Senior Science 

, 

Advisor f-Il 

/ 

~ 

THRU: 

TO: 

Katherine Stebbins, Biologist , 

Science Infonnation and Analysis Branch 

Biological and Economic Analysis Division (7503P) 

Arnet Jones, Chief 

Biological Analysis Branch 

Diann 

Science 

Sims, 

Information 

Chief A1~ and Analysis Branch 

Biological and Economic Analysis Division (7503P) 

Rochelle Bohaty, Chemist 

Environmental Risk Branch III 

Environmental Fate and Effects Division (7507P) 

BEAD Product Review Panel Date: 6/22/2011 

INTRODUCTION 

Typical use data for chlorpyrifos was requested by EFED for use in a drinking water assessment. 

In this memorandum, BEAD is providing typical use information such as the application rate and 

number of applications ror chlorpyrifos used on apples, cherries, com, grapes, grapefruit, 

lemons, oranges, onions"pecans, and sugarbeets. These data are available from a proprietary 

usage data source and are based on private matket research surveys of pesticide use in 

agriculture. In addition, data from the USDA National Agricultural Statistics Service (NASS) 

were also used as a secondary source to ensure that the usage was representative for each of the 

crops reported in this dataset. 

In addition to the national-level data, further refinement for three crops (com, sugar beets, and 

grapes) was requested by EFED for use in site-specific water models. In this memorandum, 

BEAD is also providing refined pesticide use and production practice information for com 

grown in Kansas, sugarbeets grown in Minnesota, and grapes grown in California. 
METHODS 

National Data 

Usage data for chlorpyrifos use on apples, corn, grapes, grapefruit, lemons, oranges, onions, 

pecans, and sugarbeets was compiled from a d~tabas~ of pesticide usage data. For the data years 

2006-2010, the following information was queried'· at the crop level for chlorpyrifos: pounds AI 

applied, total area treated (includes multiple applications to the same field), base area treated (the 

area treated only once), crop area grown, percent crop treated, average AI rate, the number of 

survey respondents, and the average number of applications (row crops only). To calculate the 

average number of applications for the specialty crops, the total area treated was divided by the 

base area treated to get an estimated value. -

In addition to the average application rate data, a rate distribution was generated to calculate an 

upperbound rate for each crop. The data were generated using the AI Rate Range variable (set 

from 0-7 and at an interval of 0.25) along with the total acres treated. To calculate the 

upperbound rate, the total area treated reported at each rate interval was divided by the 

cumulative total area treated across all intervals. A running total was fncluded to show the 

cumulative percentile at each rate increment and the rate associated with the 90th percent was 

reported as the upperbound rate. Therefore, the upperbound rate in this analysis can be defined 

as the rate at which 90% (or as close to 90% as possible) of the acres treated with chlorpyrifos 

were treated at or below. 

After the data were compiled, a comparison was made to the most recent data that were available 

from USDA NASS. This comparison was possible for all crops except for pecans and sugarbeets 

which are not surveyed by NASS. 

SUMMARY 

After reviewing the data from both sources, BEAD recommends using the maximum number of 

applications and the upperbound rate values presented in Table 1. 

Table 1. Typical Use Patterns for Chlorpyrifos Used on Selected Crops (2006-2010) 

Average 

Number of Number of Application Upperbound rate* 

applications applications Rate (Lbs. (Lbs. AIlAcre) 

Crop (average) (range) AIlAcre) percentile in parenthesis 

Com 1.0 1.0-1.1 0.9 1.25 (84%); 1.5 (97%) 

Sugar Beets 1.2 1.1-1.3 0.8 1.5 (88%) 

Apples 1.2 1.1-1.3 1.5 1.75 (52%); 2.0 (99.9%) 

Lemons. 1.0 1.0-1.1 3.5 5.0 (88%) 

Grapefruit 1.3 1.0-2.1 2.1 2.75 (90%) 

Oranges 1.4 1.2-1.6 2.5 5.75 (81%); 6.0 (100%) 

Onions 1.1 1.0-1.1 0.9 2 1.0 (70%); 1.25 (99.8%)2 

Cherries 1.1 1.0-1.1 1.5 2.0 (99.6%) 

Pecans 2.2 2.0-2.8 0.9 1.25 (91%) 

2 
Grapes, Raisin 1.2 1.0-1.9 1.9 2.0 (98%) 

Grapes, Table 1.1 1.0-1.4 2.7 2.25 (62%); 4.0 (100%) 

Grapes, Wine 1.2 1.0-1.4 2.0 2.0 (99.7%) 

"All Grapes" 1.2 1.0-1.4 2.2 Not availablel 

Source: GfK Kynetec. 2006-2010 

1 Recommend 4.0 pounds/A (from table grapes) as a conservative value 

2 Higher values were reported in NASS. For a conservative estimate, BEAD recommends the following: 

Avg. Rate: 1.4lbs. AI/A; Number of applications: 1, Upperbound Rate (90th percentile): 2.5 pounds/A 

(USDA NASS, 2007) 

Recommendations for Further Refinement of Three Chlorpyrifos Use Scenarios 

Corn in Kansas. Based on proprietary data (GfK Kynetec, 2010) for com, chlorpyrifos is 

primarily used by growers to control rootworm. BEAD recommends that a ground application 

be modeled. BEAD also recommends that the midpoint of the "most active" us~ planting date 

range for this state (April 15 to May 15) be used for the model input (USDA, 2010). 

Sugarbeets in Minnesota. Based on proprietary data (GfK Kynetec, 2010) and on the 

Minnesota production guide for sugarbeets, chlorpyrifos is being used by growers to control 

sugarbeet maggot. BEAD recommends using a 1.5 lb ai I A rate for the application of granular 

chlorpyrifos at-plant and a 0.5 lb ai I A rate for the second post-emergent application using the 

application instructions provided by Kahn (2011). BEAD also recommends that the midpoint of 

the "most active" usual planting date range for this state (April 24 to May 18) be used for the 

model input (USDA, 2010). 

Grapes in California. Based on proprietary data (GfK Kynetec, 2010) and pest management 

guidelines for grapes (UC IPM, 2009), chlorpyrifos is being used by grower& to control 

mealybug. BEAD recommends modeling a late February to early March delayed dormant 

application followed by a second chlorpyrifos application in late June or July (UCIPM, 2009). 

REFERENCES 

GfK Kynetec. 2006-2010 

Kahn, M. 2011. Production Guide. Sugarbeet Research and Education Board of Minnesota and 

North Dakota. Available at: http://www.sbreb.orglproductionlproduction.htm 

UCIPM. 2009. Pest Management Guidelines: GRAPE. Publication 3448, University of 

California Agriculture and Natural Resources, UC Statewide Integrated Pest Management 

Program. Available at: 

http://www.ipm.ucdavis.edulPDF/PMG/pmggrape.pdf 

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USDA NASS. 2007. Agricultural Chemical Usage-2006 Vegetables Summary-Available at: 

http://usda.mannlib.comell.edulusdalnass/ AgriChemU s Veg//2000s/2007 / AgriChemU s Ve 

g-07-25-2007 _revision. pdf 

USDA 2010. Field Crops - Usual Planting and Harvesting Dates. Agricultural Handbook 

Number 628. United States Department of Agriculture, National Agricultural Statistics 

Service. Available at: http://usda.mannlib.comell.edulusdalcurrentlplanting/planting-l 0-

29-201O.pdf 

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