expected in poultry matrices (see Section
). The metabolites IN-KT413, IN-MP819, IN-TMG00, 5-OH-
IN-JT333, 5-OH-DPXJW062 and IN-KG433 are considered unlikely to be genotoxic. The metabolite IN-
P0036 is considered as covered by studies performed with the parent compound. For the metabolites
IN-MF014, IN-MN470, IN-MK638 and IN-MT713, their toxicity pro
fi
le (including genotoxicity) cannot be
concluded; however, no data gap has been identi
fi
ed for the representative uses (see Section
).
3.
Residues
The assessment in the residue section is based on the OECD guidance document on overview of
residue chemistry studies (OECD, 2009), the OECD publication on maximum residue level (MRL)
calculations (OECD, 2011), the European Commission guideline document on MRL setting (European
Commission, 2011) and the Joint Meeting on Pesticide Residues (JMPR) recommendations on livestock
burden calculations (JMPR, 2004, 2007).
Indoxacarb was discussed at the Pesticides Peer Review Experts
’
Meeting 164 in September 2017.
Metabolism of indoxacarb in primary crops was investigated upon foliar application on pulses and
oilseeds (cotton), fruit (grapes, tomatoes) and on leafy (lettuce) crop groups using the racemic
mixture DPX-JW062
14
C-labelled on the indanone moiety and the tri
fl
uoromethoxyphenyl ring,
respectively. In all crops and for both labellings, indoxacarb (racemic mixture) was the main compound
of the total radioactive residues (TRR) accounting for up to 84% TRR in mature cotton leaves, 95%
TRR in grapes, 99% TRR in lettuce and up to 87% and 97% TRR in tomato fruit and leaves,
respectively. The TRRs in mature cotton seeds were too low (
<
0.01 mg/kg) to perform further
metabolites
’
identi
fi
cation. In mature cotton leaves and tomato fruits and leaves, the
S/R
isomeric ratio
remained unchanged (1:1) indicating no preferential metabolism of either enantiomer in those crops.
It is therefore unlikely that any further metabolism study conducted with the
S
-isomer only
(indoxacarb) will lead to a different metabolic pattern. Considering also that the
R
- and
S
- isomers
were concluded to be of similar toxicity (see Section
), the experts of the meeting agreed that
suf
fi
cient metabolism data are available to fully address the metabolism of indoxacarb in plants and a
general residue de
fi
nition for monitoring and risk assessment in plants can be set as indoxacarb (and
its
R
-enantiomer).
A con
fi
ned rotational crop metabolism study was conducted following a bare soil application (2N
rate) with
14
C-indoxacarb labelled either on the indanone moiety or on the tri
fl
uoromethoxyphenyl ring
in root crops (carrot), leafy crops (lettuce), cereals (wheat) and pulses and oilseeds (soya bean) at 36,
90 and 125 days plant-back intervals (PBIs). The study was not compliant with the current guidance
recommendations in view of the lack of metabolites
’
identi
fi
cation in any edible part of the crops and
signi
fi
cant proportions of unextracted radioactive residues (12
–
52% TRR). The metabolic pattern of
indoxacarb in rotational crops could therefore not be elucidated. Having regard to the medium to high
persistence in soil of indoxacarb (DT
50
=
65.3
–
321 days) and of its metabolites: IN-MK643
(DT
50
=
123.3
–
314.2 days), IN-ML438 (DT
50
=
80.9
–
186.5 days), IN-JT333 (DT
50
=
19.6
–
147.5 days)
and IN-JU873 (DT
50
=
24.8
–
103.5 days), a data gap was identi
fi
ed to provide con
fi
ned rotational crops
metabolism studies addressing the potential uptake and fate of these compounds in leafy crops, small
grain crops and root crops and to enable the calculation of reliable soil/plant transfer factors for the
parent indoxacarb and all relevant compounds. The need for further rotational crops
fi
eld residue trials
conducted at a dose of application covering the maximum predicted plateau concentration in soil of
indoxacarb and all relevant compounds will have to be reconsidered accordingly.
Under standard hydrolysis conditions, indoxacarb was found to be stable under pasteurisation
whilst it was degraded into IN-KT413 under baking/brewing/boiling conditions (14% of the applied
radioactivity (AR)) and into the following metabolites under sterilisation: IN-KT413 (28.7% AR), IN-
MP819 (10% AR), IN-MK638 (10% AR), IN-P0036 (16% AR) and IN-TMG00 (12.4% AR). Processing
residue trials were submitted on tomatoes, grapes, apples, peaches and maize analysing for residues
of indoxacarb and its
R
-enantiomer in processed commodities. Further processing residue trials
analysing for metabolites IN-KT413, IN-MK638, IN-P0036 and IN-TMG00 in canned apples, peaches
and green beans demonstrated that these compounds were never detected (
<
LOQ). The validity of
these trials was discussed as these were not representative of the most critical conditions of
sterilisation and cannot therefore be considered to rule out the occurrence of these metabolites in
processed commodities. It is also noted that IN-MP819 was never analysed in any processed
commodity, and
fi
nally, these processing residue trials were not supported by storage stability data to
demonstrate the integrity of residues of all relevant compounds. For processed commodities, the
residue de
fi
nition for monitoring is proposed as indoxacarb (and its
R
-enantiomer) while for risk
Peer review of the pesticide risk assessment of the active substance indoxacarb
www.efsa.europa.eu/efsajournal
11
EFSA Journal 2018;16(1):5140