Reporting of Residue Trials

Residue Guideline No. 11
February 2000


The purpose of this guideline is to outline the minimum data required to support the maximum residue limits (MRL) proposals for registration.  Sufficient data must be submitted in the report so that reviewers are able to completely understand how the study was conducted, the results derived and thus ascertain that the study was scientifically valid.

The report should outline the purpose of the study, describing the methods and materials used and the presentation of the results, including statistical analysis (where appropriate), in a suitable format.  Discussion of the results should be given to permit a recommendation on the MRL and proposed withholding period relative to the label use pattern.

The format of the report should include, but not necessarily be limited to the following:


Summary of the application details and the results of the trials.


Reason for the trials and objectives.


(i)      Site details

Location of trial(s)[1]:

Type of application:   e.g. seed treatment;  plants/soil sprayed to run-off, band etc; animals - pour-on, oral, dermal etc.

Equipment used:   e.g. mist blower, knapsack, boom sprayer etc; animals - shower, jetting, dipping.

Test system:   Crop/variety   Animal/breed

Planting date    Summer/winter Coat Timing off shears

Growth stage    Age Lactation period

Soil type    Dip capacity

Plot dimensions    Covered or open pens

No. of replicates/    No. of animals/

treatment [2]    treatment

No. controls    No. controls

Cultivation    Feed regime

Other treatments    Other treatments

applied    applied

(ii)          Application details

Test substance(s):   Including batch number; formulation number; formulation type; assay and/or stability data as applicable.

Product rate[3]   g/ha, mL/100L, % solution, mL/kg bodyweight of animal.

Volume applied:   L/ha, litres of spray.

Timing between treatments:   days, weeks, months.

Date(s) of application(s):

(iii)          Sampling

Part of crop/animal sampled

Soil depth of sampling if applicable

Sample weight and number of units per replicate if applicable

Date(s) of sampling[4]

Method of sampling[5]

Growth stage/animal weight at sampling (including normal harvest date if applicable)

Method of storage and shipment of samples from field site to laboratory

Storage conditions [6] from time of collection/shipment/analysis

(iv)    Preparation of sample [7]

Details should be provided on how the samples are prepared for analysis such as sub-sampling, chopping, mixing, grinding.  Details should be provided on any pre-treatment carried out such as removal of fat, washing, peeling, soil removal.

An homogenised sample is essential if a meaningful result is to be obtained.

(v)    Analysis details [8]

Summary of the method (uniquely numbered) should be given in the report.  The entire method must be provided for registration either as an appendix to the report or with the submission.

(vi)    Conduct of trial

Name(s) of people responsible for the trial and collection of samples.

The address of the facility carrying out the analysis and the name(s) of the analyst(s) responsible.

The period in which the analysis was carried out.



All results should be quoted including controls and recoveries.  Results should be expressed as defined by Codex [9] e.g. dry weight basis or whole fruit basis.

Representative recoveries should be determined at levels where residues are likely to occur.  Indicate whether results have been corrected for recoveries or not.

Results of individual analysis should be reported and not averaged.


Conclusions should be made to permit a recommendation to be made on the MRL and proposed withholding period relative to the label use pattern.  Where applicable, climatic effects should be discussed.  The discussion should include any aspects of the report which require explanation, including any unexpected results.


(i)      Weather

Where relevant (not required for internal animal treatment) weather details should be provided at or as close to the site(s) as possible.  Include rainfall/irrigation and air temperature on day of application and daily for 1  week afterwards. Thereafter data can be averaged on a weekly or monthly basis depending on the length of the trial.

(ii)     Soil type

When the test material is applied directly to the soil include data on soil classification e.g. soil type, pH and organic matter.


Food and Agriculture Organisation of the United Nations (FAO). Guidelines on Producing Pesticide Residue Data from Supervised Trials. Rome, 1990.

[1]     The number of sites/trials needed depends upon the different ecological and climatic conditions in which the use of the product is intended.  Sufficient data must be available to confirm that the patterns determined cover the range of conditions likely to be met during the intended use of the pesticide, including those which are likely to give rise to the highest residues.

[2]     Since the variations in residue levels between replicates at individual sites are small compared with those between sites, it is usually not necessary to replicate treatments at more than one site.  Studies with only one sampling (e.g. harvest) require at least two sub-samples from each half of the plots. The samples taken are analysed separately.

[3]     Application should be carried out at the proposed maximum label rate and timings and at an exaggerated rate, usually from 1.5-2 times the maximum label rate. Applications (single and exaggerated rates) may also be carried out at timings closer to harvest, shearing or slaughter than label recommendations in order to demonstrate that unacceptable residues will not eventuate if applied later than normally recommended, and to cover for new varieties/breeds with different development patterns.  Each study must have a control (not treated with the test compound or chemically related compound).

[4]     The sampling regime is dependent on the persistency of the pesticide residues and must include the time of any proposed withholding period (see Residue Guideline No. 10, Withholding periods)

[5]     Samples should be taken first from the control group then from the lowest to the highest application.  A specific description should be given as to how the sample was taken and what was done to ensure the sample was representative.

[6]     Further information is given in Residue Guideline No. 8, Stability of residues during storage.

[7]     Part or whole of the sample to be analysed, as defined in: Codex Alimentarius Commission, Codex Classification of Foods and Animal Feedstuffs, Part 4: Guide to Codex recommendations concerning pesticide residues, FAO, Rome, 1989.

[8]     For more details refer to Residue Guideline No. 19, Residue analytical methods.

[9]   Codex Alimentarius Commission. Codex Classification of Foods and Animal Feedstuffs (second edition) FAO, Rome, 1989.

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