Reasoned opinion on the review of the existing maximum residue levels (MRLs) for acibenzolar-S-methyl according to Article 12 of Regulation (EC) No 396/2005


European Food Safety Authority
EFSA Journal
EFSA Journal 2013;11(2):3122 [41 pp.].

EFSA wishes to thank the rapporteur Member State France for the preparatory work on this scientific output.

Reasoned Opinion
On request from
Question Number
20 February 2013
25 February 2013
European Food Safety Authority (EFSA), Parma, Italy
Download Article (789.19 KB)

According to Article 12 of Regulation (EC) No 396/2005, the European Food Safety Authority (EFSA) has reviewed the Maximum Residue Levels (MRLs) currently established at European level for the pesticide acibenzolar-S-methyl. In order to assess the occurrence of acibenzolar-S-methyl residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC as well as the import tolerances and European authorisations reported by Member States (incl. the supporting residues data). Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, some information required by the regulatory framework was found to be missing. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers.


Acibenzolar-S-methyl was included in Annex I to Directive 91/414/EEC on 01 November 2001, which is before the entry into force of Regulation (EC) No 396/2005 on 02 September 2008. EFSA is therefore required to provide a reasoned opinion on the review of the existing MRLs for that active substance in compliance with Article 12(2) of the aforementioned regulation. In order to collect the relevant pesticide residues data, EFSA asked France, as the designated rapporteur Member State (RMS), to complete the Pesticide Residues Overview File (PROFile). The requested information was submitted to EFSA on 14 April 2009 and, after having considered several comments made by EFSA, the RMS provided on 15 December 2009 a revised PROFile.

Based on the conclusions derived in the framework of Directive 91/414/EEC and the additional information provided by the RMS, EFSA issued on 29 May 2012 a draft reasoned opinion that was circulated to Member States’ experts for consultation. Comments received by 03 August 2012 were discussed in a meeting of experts, which took place on 23 November 2012, and the outcome of that meeting was considered for finalisation of this reasoned opinion. The following conclusions are derived.

The toxicological profile of acibenzolar-S-methyl was evaluated in the framework of Directive 91/414/EEC which resulted in an ADI of 0.1 mg/kg bw per d. An ARfD was not deemed necessary.

Primary crop metabolism of acibenzolar-S-methyl was investigated on three different crops using foliar application treatment. These crops are representative of cereals (wheat), fruits and fruiting vegetables (tomatoes) and leafy vegetables (tobacco, lettuce). During the consultation of member states it was agreed that a general residue definition for enforcement and risk assessment should be set as the sum of acibenzolar-S-methyl and acibenzolar-acid (free and conjugated), expressed as acibenzolar-S-methyl. Analytical methods for enforcement of this residue definition in plants are available with a LOQ of 0.01 mg/kg in high water, dry and high oil content commodities. In future, further information on the occurrence of free acid in plant commodities would be desirable in order to simplify the residue definition for enforcement to acibenzolar acid only.

Regarding the magnitude of residues in primary crops, a sufficient number of supervised residue trials is available for the GAPs reported by the RMS, which allowed EFSA to estimate the expected residue concentrations in the relevant plant commodities and to derive adequate MRLs, except for apples and pears where further clarification on the discrepancies observed in the apple and pear residue trials is required, and for mangoes where further residues trials are still needed to support the MRL proposal.

The nature of residues in processed commodities was considered following the inclusion of acibenzolar-S-methyl in Annex I and it was concluded that the same residue definition as for primary crops can be applied to processed commodities. Studies investigating the magnitude of residues in processed commodities of tomatoes were reported in the PROFile submitted by the RMS. Robust processing factors for enforcement and risk assessment could be derived for peeled tomatoes (0.65) and tomato paste (1.88). Further processing studies are not required as they are not expected to affect the outcome of the risk assessment. However, if more robust processing factors were to be required by risk managers, in particular for enforcement purposes, additional processing studies would be needed.

The fate of acibenzolar-S-methyl residues in rotational crops of lettuce, radish, winter wheat and maize was investigated during the peer review. All residue levels in the crops were found to be equal or below 0.001 mg/kg.  Consequently, residue levels in rotational commodities are not expected to exceed 0.01 mg/kg, provided that acibenzolar-S-methyl is applied in compliance with the GAPs reported in Appendix A.

The nature of acibenzolar-S-methyl residues in commodities of animal origin was investigated in the framework of Directive 91/414/EEC. Reported metabolism studies include one study in lactating goat and one study in laying hen. However, it was agreed during the consultation of Member States that no residue definition or MRLs would be required for products of animal origin based on the following observations; the calculated dietary burden for meat ruminants was the only one to slightly exceed the trigger value of 0.1 mg/kg, low absolute levels in the animal metabolism studies were observed and in the available feeding studies all residues in products of animal origin were below the LOQ, despite the exaggerated 10N dose rate. An analytical method for enforcement of residues in food of animal origin is not necessary.

Chronic consumer exposure resulting from the authorisations reported in the framework of this review was calculated using revision 2 of the EFSA PRIMo. For those commodities where data were insufficient to derive an MRL, EFSA considered the existing EU MRL for an indicative calculation. The highest chronic exposure was calculated for WHO cluster B representing 0.7 % of the ADI. Acute exposure calculations were not carried out because an ARfD was not deemed necessary for this active substance.

Based on the above assessment, EFSA does not recommend inclusion of this active substance in Annex IV to Regulation (EC) No 396/2005. MRL recommendations were derived in compliance with the decision tree reported in Appendix D of the reasoned opinion (see summary table). All MRL values listed as ‘Recommended’ in the table are sufficiently supported by data and therefore proposed for inclusion in Annex II to the Regulation. The remaining MRL values listed in the table are not recommended for inclusion in Annex II because they require further consideration by risk managers (see summary table footnotes for details). In particular, certain tentative or existing EU MRLs still need to be confirmed by the following data:

  • 2 additional trials supporting the GAP on mangos;
  • further clarification on the discrepancies observed in the apple and pear residue trials.

Minor deficiencies were identified in the assessment but these deficiencies are not expected to impact either on the validity of the MRLs derived or on the national authorisations. The following data are therefore considered desirable but not essential:

  • further information on the occurrence of free acid in plant commodities in order to simplify the residue definition for enforcement to acibenzolar acid only;
  • 1 additional trial on tomato complying with the indoor GAP;
  • 4 trials on apricots compliant with the southern outdoor GAP on peaches and apricots (data gap resulting from a new extrapolation rule).
acibenzolar-S-methyl, MRL review, Regulation (EC) No 396/2005, consumer risk assessment, benzothiadiazole, plant growth regulator
Print on demand
Number of Pages