Pesticide Registration Toolkit

#706 Residue trials for crops or plant products used as food or feed

Objective of the study

Supervised field trials (crop field trials) are conducted to determine pesticide residue levels in or on raw agricultural commodities, including feed items, and should be designed to reflect pesticide use patterns that lead to the highest possible residues. Objectives of crop field trials are to:

  • quantify the expected range of residue(s) in crop commodities at the time of normal harvest following treatment according to the proposed or established good agricultural practice (GAP);
  • determine, when appropriate, the rate of decline of the residue(s) of the pesticide(s) on commodities of interest;
  • determine residue values such as the Supervised Trial Median Residue (STMR) and Highest Residue (HR) for conducting dietary risk assessment;
  • derive maximum residue limits (MRLs).

As a general precondition, for reliable estimation of maximum residue levels an adequate number of independent trials are required reflecting the highest of national maximum GAPs and conducted according to well-designed protocols that consider geographical distribution and the inclusion of a number of different growing and management practices, and growing seasons.

Further information on residue trials for crops or plant products can be found in Chapter 3.5 of the JMPR Procedure Manual.

Worked examples on this topic are provided in Chapters 7 and 8 of the JMPR Training Manual


Circumstances in which the study is required

Residue trials should always be performed where the pesticide is to be applied to plants or plant products that are used as food or feed, or where residues from soil or other substrates can be taken up by such plants, except where extrapolation from adequate data on another crop is possible.

Residue decline data are required for those uses where the pesticide is applied when the edible portion of the crop has formed, or it is expected that residues may occur on the food or feed commodities at, or close to, the earliest harvest time.


Test conditions

Supervised residue trials shall correspond to the proposed critical GAP. The test conditions shall be defined to identify the highest residues which may reasonably arise (e.g. maximum number of proposed applications, shortest interval between applications, maximum application rate and concentration, most critical safety intervals with regard to exposure) and shall be representative of the realistic conditions in which the pesticide is to be used.

The number of trials (generally minimum 6–10) and samples is dependent on the variability of use conditions, the consequent scatter of the residue data, and the importance of the commodity in terms of production, trade and dietary consumption. Residue data should be available from trials, preferably carried out in at least two separate years or at least representative of different weather conditions in accordance, or approximately in accordance, with Good Agricultural Practice. If uses are authorised in regions with substantially different climatic conditions, trials should also be carried out in each region. Residue data from only one season may be considered sufficient provided that crop field trials are located in a wide range of crop production areas such that a variety of climatic conditions and crop production systems are taken into account.


Test substance

Residue field trials are conducted with a typical end product (formulation), relevant for the GAP for which registration is sought.


Typical endpoints of the study

Residue of the pesticide (and relevant metabolites) expressed as mg a.i./kg substrate.

For a series of supervised residue trials, corresponding to the critical GAP, endpoints are the Supervised Trials Median Residue (STMR) and the Highest Residue (HR)


Testing guidelines

The following testing guidelines may be used for crop field trials: