Washington Tree Fruit Research Commission

Research Reports

Magnitude of the Residue Evaluation for Applaud 70WP on Pears (2002)

WTFRC Project #
YEAR 0/0
Organization Project #
Title:Magnitude of the Residue Evaluation for Applaud 70WP on Pears
PI:Vincent R. Hebert
Organization:Food and Environmental Quality Laboratory, WSU TriCities
 PDF version of report


Doug Walsh, Washington State IR-4 Liaison Representative, WSU Prosser, WA

Chuck Mourer and Matt Hengel, IR-4 Western Regional Laboratory, UC Davis, CA




The USDA Interregional–4 (IR-4) Minor Crop Project has received a petition from Washington for securing a tolerance for Applaud 70WP in pear production.  The active ingredient in this formulation is the insect growth regulator, buprofenzin.  This formulation is expected to be efficacious against pear psylla without appreciably altering the complex of natural enemies of this pest.  This request has been given an “A” priority by IR-4 and fieldwork was completed in 2001.  WSU’s Food and Environmental Quality Laboratory  (FEQL) was asked to provide residue analysis for buprofenzin in pears.  The IR-4 tolerance submission for this safer material should receive “fast track” registration attention by EPA since it is considered a reduced risk pesticide.  Funding from the Pear Review Board was requested by FEQL to provide quality assurance and technical support to complete the analytical portion of this study in a timely manner for “fast track” registration purposes.  Proposal objectives were stated as follows:


  1. Analyze total residues of buprofezin (i.e., active ingredient of ApplaudÒ 70WP) in/on pears collected from Magnitude of the Residue field trials conducted according to commercial application practices.
  2. Complete residue analyses and reporting within 6 months after receiving field samples for timely registration of this material for use in pesticide resistance management practices.
  3. Complete all phases of analytical work by February 2002.
  4. Work with IR-4 to have a reduced risk registration package submitted to EPA in 2002.


All stated objectives in the FY 2001 proposal will be completed on time.  Residue analyses were completed within 6 months of sample receipt (objective 2).  The finalized/audited analytical report will be submitted to IR-4 by February 2002 (objective 3), and the P.I. is coordinating with IR-4 to help guarantee the 2002 delivery of pear residue data to the EPA for an expedited registration as a “reduced risk pesticide” (objective 4). 


Significant findings

Eight field locations representative of major pear production in the U.S. (three in the PNW) were treated twice with Applaud 70 WP at a maximum use rate (1.58 lb/A/app.) with a minimum 14-day pre-harvest interval.  Two plots were involved with each site: a treated and non-treated plot.  Duplicate samples were taken from each of the two plots (i.e., 2 duplicates x 2 plots x 8 locations, or 32 total samples).  The analytical residue method used in this study was derived from a method provided by AgrEvo, RAM number: BF/10/97: “An Analytical Method for the Determination of Residues of Buprofezin at Estimated Tolerance Levels in Almonds, Cottonseed, Citrus (Lemons), and Grapes by Gas Chromatography Using Nitrogen Phosphorus Detection.” Modifications to the above method for the specific requirements of analyzing buprofezin residues on pears are stated in the modified working method: “Working Method for Determination of Residues of Buprofezin in Pears by Gas Chromatography Using Nitrogen Phosphorus Detection (FEQL Project No.: FEQL-0101) as part of the residue report.  Over the course of analyses, ample quality control samples (calibration standards, blanks, fortified and non-treated samples) were assessed to guarantee the integrity and precision of analysis. The above field and analytical work was performed under strict conformance to 40CFR Part 160 Good Laboratory Practice Standards.  An independent Quality Assurance Unit inspected critical phases during the analyses and audited all data and analytical report findings.


The method validation set, together with concurrent quality control samples (fortification recoveries) ran during analyses indicate the working method accurately reflects encountered buprofezin residues from a two application program conducted at 1.58 lb. a.i./A/app. with a minimum 14-day PHI.  Validation, recovery and residue results from the eight treatment plots were as follows:




                                      Percent Recoveries
Standard Dev.


Validation Range %
Recovery Range %




         Sample location
Untreated Control
(in ppm)
Duplicate Treated Samples
(in ppm)


California trial
0.31, 0.40
California trial
0.57, 0.60
California trial
0.81, 1.11
Washington trial
0.68, 0.60
Washington trial
1.31, 1.12
Idaho trial
2.70, 3.64
Colorado trial
1.09, 0.71
New Jersey trial
0.71, 0.86


The maximum residue encountered was from the Idaho trial at 3.6 ppm.  The results suggest that IR-4 will most likely propose a residue tolerance of 5 ppm according to the two application 1.6 lb/A/ app., 14-day PHI use pattern to the EPA for registration approval.  



Exact copies of the original raw data, protocol, correspondence logs, and all relevant information for the GLP study titled: “Magnitude of the Residue Evaluation for Applaud® 70WP on Pears”, PR. No. 07518, among with a certified copy of the signed analytical summary report will be maintained in the archives at FEQL. The original protocol, data, analytical summary report, and relevant information for the construction of this study will be transferred to IR-4 national headquarters in Rutgers, N.J.  A certified true copy of the ca. 60-page GLP final residue report will be provided to the Pear Review Board through the Washington State Tree Fruit Research Commission in February 2002.

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