IPCS INCHEM Home



    PESTICIDE RESIDUES IN FOOD - 1979


    Sponsored jointly by FAO and WHO






    EVALUATIONS 1979





    Joint meeting of the
    FAO Panel of Experts on Pesticide Residues
    in Food and the Environment
    and the
    WHO Expert Group on Pesticide Residues
    Geneva, 3-12 December 1979



    DIPHENYLAMINE

    Explanation

    Diphenylamine was first evaluated in 1969 when an ADI was allocated
    and a MRL for apples.  In 1976 additional toxicological and residue
    data from Australia and the Netherlands were received and the meeting
    confirmed the ADI and recommended that, unless countries had a need to
    maintain the MRL for apples at 10 mg/kg, it should be reduced to 5
    mg/kg.

    Residue data have been generated in Australia and additional
    information has been obtained from USA and the open scientific
    literature to permit the meeting to further evaluate the MRL.

    RESIDUES IN FOOD AND THEIR EVALUATION

    Since the evaluation in 1976 indicated that residues on apples are
    generally less than 2 mg/kg, the data considered in 1969 have been
    re-evaluated with a view to seeking an explanation for the higher MRL
    proposed on that occasion.  The difference can be explained by the
    following:

    1.  The concentration of diphenylamine dip solutions used over recent
    years is substantially less than those used in experiments in the late
    1950's.

    2.  The quality and stability of the formulation has an important
    bearing on the amount of diphenylamine deposited on fruit from dips
    and sprays.  The quality of diphenylamine emulsion and wettable powder
    formulations has been improved considerably with a result that they
    give more uniform and lower deposits.

    3.  All of the residue data reported by Harvey and Clark (1959) and
    apparently much of that reported by Bruce (1958) used as a basis for
    the evaluation in 1969, refer to residues in the peel rather than the
    whole fruit.  These and later studies have usually shown that the
    concentration is much higher in the peel than in the whole fruit.

    Importance of formulation and stability of dips

    Denmead et al (1961) used a diphenylamine emulsion which was
    homogenised by passing five times through a colloid mill until a
    uniform globule size was achieved; most globules being between 1 and 4
    microns diameter, with very few exceeding 5 microns.  It was noted
    that without homogenisation less uniform emulsions with much larger
    globules were formed and that these coarse emulsions gradually broke
    down during their passage through the spray equipment.  Diphenylamine
    uptake was found to be negatively correlated with globule size and
    until fine uniform emulsions were formed, it was not possible to
    obtain reproducible uptake of diphenylamine.

    During drenching operations the diphenylamine concentration in the dip
    gradually fell as a result of uptake of diphenylamine by apples and
    dilution of the emulsions by water introduced on the wet apples.  The
    concentration of the bath before and after treatment differed by as
    much as 30 percent.

    Gorman and Row (1977) investigated the properties of two different
    commercial diphenylamine formulations and showed that emulsion
    breakdown was accompanied by phytotoxicity due to the uneven and
    excessive deposition of diphenylamine on the skin of fruit.  The
    practice of combining calcium chloride with diphenylamine dips to
    control bitter pit as well as superficial scald can result in rapid
    breaking of the emulsion.  The spraying operation, which greatly
    increased aeration, also resulted in the rapid breaking of the
    diphenylamine emulsion.  The quality of the water used for diluting
    the emulsion also had a distinct bearing on its stability.

    Gorman and Rowe (1977) also showed that stable formulations give a
    lower deposit on apples and consequently are not as effective in
    controlling superficial scald.  This can be overcome by increasing the
    concentration in the dip bath.  In dipping tests, one preparation
    yielded initial deposits three to six times higher than the more
    stable preparation applied at the same concentration for the same
    time.  The unstable emulsion tended to give a much higher deposit when
    the dip time was increased from 60 to 180 seconds.  The residual
    deposit from the stable preparation was not significantly affected by
    the dipping times.

    Little et al (1977) drew attention to the effect of additives (calcium
    chloride, benomyl and on fruit susceptibility to phytotoxic damage.
    Calcium chloride benomyl caused the active ingredient to be stripped
    out rapidly onto the fruit.

    Denmead et al (1961) used a standard diphenylamine solution in oil,
    emulsified with water to prepare a range of concentrations from 0.05%
    to 0.3%.  These were used to dip two varieties of apples.  The uptake
    of diphenylamine was measured by analyzing the fruit.  Hanekom et al
    (1976) demonstrated the effect of immersion time and diphenylamine
    concentration on the uptake of diphenylamine by Granny Smith apples.
    This could be readily correlated to the percentage reduction of
    superficial scald.  Their results are summarised in Table 1 (see also
    comment under "Residues resulting from Supervised trials, Cornell
    University.)

    Table 1.  Effect of immersion time and DPA concentration on the uptake
    of DPA (ppm) by Granny Smith apples (Percentage superficial scald
    given in brackets)

                                                                           
    Immersion time (sec.)             DPA concentration (ppm)
                                  600             1200             1800
                                                                           
             30                0.7  (91)        1.7  (83)        1.6  (78)
             75                1.4  (80)        1.7  (95)        2.4   (77)
            120                1.8  (74)        2.5  (71)        3.5   (4)
                                                                           

    LSD (P = 0.05) Immersion time  DPA concentration = 0.6
    Constant factors:
    Picking stage = 150 days
    Fruit Temperature = 20C
    Temp. of immersion solution = 20C

    Hanekom at al (1976)


    Application temperature

    Hanekom et al (1976) investigated the effect of fruit temperature and
    temperature of immersion solution on the uptake of diphenylamine by
    Granny Smith apples and showed that this was readily correlated with
    percentage superficial scald.  Optimum results were obtained when the
    immersion solution was at 40C and the fruit temperature between 10C
    and 20C.  Their results are given in Table 2.  The higher
    temperatures lead to higher deposits on the fruit.

    Table 2.  Effect of immersion solution and fruit temperatures on the
    uptake of DPA by Granny Smith apples (Percentage superficial scald
    given in brackets)

                                                                  
    Temp. of immersion              Fruit temperature (C)
    solution (C)          -0,5          10            20
                                                                  

           20              1.0  (91)     1.0  (100)    2.4  (89)
           30              1.8  (85)     1.4  (84)     2.6  (50)
           40              3.2  (30)     3.8  (0)      3.6  (2)
                                                                  
    LSD (P = 0.05) Immersion solution  fruit temperature = 0.7
    Constant factors:
    DPA concentration of immersion solution = 1 200 ppm
    Picking stage = 150 days
    Immersion time = 75 sec.

    Hanekom et al (1976)

    Effect of variety

    The diphenylamine uptake was measured for a number of varieties of
    apples in studies by Denmead et al (1961).  A 0.2 percent emulsion of
    diphenylamine was applied as a drench for one minute and the uptake
    was determined by analyzing the fruit.  The results are given in Table
    3.

    Table 3.  Variation of DPA uptake with variety

                                                    
                                 DPA uptake
    Variety                      gamma/cm2
                                                    
    Worcester Pearmain             14.5
    Gravenstein                    14.5
    Cox's Orange Pippin             6.8
    Ballarat (1)                    4.0
    Ballarat (2)                    1.6
    Dougherty                       2.9
    Granny Smith (1)                1.0
    Granny Smith (2)                0.76
                                                    
    Denmead et al (1961)


    Effect of size of fruit on uptake of diphenylamine

    Since superficial scald and diphenylamine uptake are both surface
    phenomena, some investigators have expressed the diphenylamine
    concentration as mg/cm2 rather than as mg/kg, though the former
    figure is not suitable for expressing residue concentration.  The
    surface area of apples was obtained by assuming them to be spheres and
    applying the surface to volume relationship of a sphere (Denmead et al
    1961).  When the concentration of diphenylamine expressed as mg/cm2
    and mg/kg on 8 apples of different weights were plotted against
    surface area and weight respectively, it was apparent that the
    diphenylamine concentration expressed as mg/kg was negatively
    correlated with the weight of individual apples whereas when expressed
    as mg/cm2 it was independent of surface area.  For an apple weighing
    180 g with a volume of 220 ml for example, the values of diphenylamine
    uptake expressed as either mg/kg or mg/cm2 were numerically equal. 
    For larger apples the mg/kg figure became progressively smaller than
    the mg/cm2 and conversely for smaller apples.

    Rate of loss on storage

    Hall et al (1961) showed that the concentration of diphenylamine on
    apples fell greatly during storage.  The concentration in the skin at
    the end of seven months was only about 1/30th of that in the skin at
    the time of treatment.  The concentration in the whole apple fell by a
    like amount.

    Table 4 (Denmead et al, 1961) sets out the initial and final
    diphenylamine concentrations on three varieties of apples held in cold
    storage.  By measuring diphenylamine concentration at intervals during
    storage, the rate of loss was obtained for a sample of Doughtery
    apples.  When the concentrations were plotted against storage times
    for four samples of different initial concentrations, the rate of loss
    was found to be almost constant and independent of the amount applied
    to the apple.

    Table 4. Loss of DPA from apples during storage

                                                                        
                                                 DPA concentrations
                     Storage         Before storage         After storage
    Variety          period                 Co-efficient
                      days       p.p.m.    of variation %      p.p.m.
                                                                        
    Granny Smith      199    )    15.6           18             1.0
                             )    11.0           22             0.9
                             )     4.5           11             0.4
                             )     1.8           14             0.3

    Ballarat          207    )     6.7           11             0.5
                             )     4.6           16             0.3
                             )     1.4           22             0.2

    Dougherty        172     )    12.4            9             1.1
                             )     4.8            8             0.5
                             )     1.4           11             0.3
                                                                        

    Denmead et al (1961)


    Distribution on fruit

    With the exception of Ginsburg (1962) all authors appear to agree that
    the bulk of the residue is located in the natural wax on the fruit
    with over 90% occurring in the peelings.

    Harvey and Clark (1959) report that irrespective of variety, method of
    treatment or concentration of diphenylamine applied, over 95% of the
    diphenylamine is distributed in the peeling even after the fruit has
    been in cool storage for lengthy periods.

    Hanekom et al (1976) studied the percentile distribution of
    diphenylamine in different fractions of the fruit after different
    storage periods.  Whilst there was a tendency for apples, in which
    superficial scald was completely controlled, to have significantly
    more in the cuticle wax layer, all fruit had from 52-77% in the wax
    layer with as little as 1.3 to 5.6% in the hypodermis.  This is
    important as the diphenylamine is mainly restricted to parts of the

    fruit where superficial scald initiates and develops, and therefore
    the treatment is specifically effective at the site where it is most
    needed.

    Hall et al (1961) reported diphenylamine was practically confined to
    the peel irrespective of the level and method of treatment or the time
    in storage.  These observations were borne out in recent studies in
    Australia (Luke 1978, Gorman and Rowe, 1977).  However, Ginsburg
    (1962) using the methods of Harvey (1958) found that the amount of
    diphenylamine remaining on the surface was negligible and the amount
    found in the pulp was always much higher than in the skin except in
    one instance.  The one difference in technique was that most reports
    in the literature are for studies carried out on apples immediately
    after cold storage, whilst the work reported by Ginsburg was done
    after the apples had been held at room temperature (15-20C) for one
    week.

    Luke (1978), reporting the results of analysis of approximately 50
    different samples, treated both with dips and paper wraps, from many
    parts of Australia, showed that diphenylamine does not penetrate
    beyond 2-4 mm from the peel surface and that the residue levels in
    peel are similar to those reported by Harvey and Clark (1959).

    RESIDUES RESULTING FROM SUPERVISED TRIALS

    The work of Harvey and Clark (1959) reviewed by the meeting in 1969
    refers entirely to levels of residues found in peelings and pulp and
    nowhere in the paper is any attempt made to report or calculate these
    on the whole fruit basis. (But this fact is not clear in the 1969
    monographs.)  Luke (1978) reviewed the data in the light of Australian
    experience, and calculated the approximate level in using his own
    experience of the ratio of skin to whole fruit.  He found the
    diphenylamine residue level on whole fruit for the data reported by
    Harvey and Clark to range from less than 0.1 mg/kg to 0.4 mg/kg. 
    Bruce et al (1958) found 3.23 to 3.64 mg/kg diphenylamine residue
    immediately after use of a 1000 mg/l bath and 1.59 to 1.77 mg/kg after
    5 months storage.

    Hall et al (1961) have published the results of extensive trials which
    encompass most of the variables likely to be encountered in practice.
    With the exception of residues determined in fruit one day after
    dipping, all values recorded for whole fruit were 1 mg/kg or less. 
    The high values recorded immediately after treatment decreased to
    about 2 percent of the original level during the time the fruit was in
    cold storage.

    The USDA (1961) reported studies carried out in Wenatchee, Washington,
    in which the effect of four variations of treatment and storage times
    were examined.  Residues on the surface and in the pulp were
    determined separately.  Results are given in Table 5.  The total
    diphenylamine residue ranged from 5 mg/kg immediately after dipping to
    0.5 mg/kg after storage for nine months.  The pulp contained a higher
    fraction of the total residue in the samples which had been stored for

    two months (58%) or nine months (52 to 83%) than was the case one day
    after dipping (18%).  The colorimetric procedure (Bruce et al 1958)
    used in these investigations gave a high apparent value in untreated
    control samples.

    Cornell University (1962), reporting trials carried out in 1961 at
    Ithaca, N.Y., showed that the nature and stability of the formulation
    was critical in determining the level and uniformity of diphenylamine
    deposits on apples.  The report points to unsatisfactory results
    obtained with alcoholic solutions due to the deposition of crystals of
    diphenylamine in the dipping bath.  When satisfactory wettable powder
    formulations were used the deposit, determined immediately after
    treatment, remained generally below 3 mg/kg irrespective of the
    concentration of diphenylamine in the dip bath (Table 6 and 7) or
    whether the treatment was carried out immediately after harvest or
    after a period in cold storage (Table 8).

    All of the data reported by Ginsburg (1962) are for fruit which has
    been held in cold storage for an extended period and then for one week
    at room temperature (15C to 20C) prior to analysis.  The
    diphenylamine residue level on whole fruit at the end of this storage
    in all cases was well below 1 mg/kg, usually below 0.2 mg/kg.

    Gorman and Rowe (1977) report that laboratory dipping trials with
    different formulations produced residues of the order of 2 mg/kg to 4
    mg/kg on the day of treatment, but that these had fallen, to less than
    1 mg/kg after 14 to 28 days in cool storage.  Unstable formulations
    used at high dip concentrations gave rise to residues which after 21
    days in storage at minus 0.5C ranged up to 2.5 mg/kg.

    Hanekom et al (1976) report the level of residues in whole apples,
    four days after immersion for various periods in diphenylamine
    emulsions at several concentrations.  The highest concentrations and
    longest time gave rise to residues of the order of 3.5 mg/kg, though
    this concentration fell to approximately half during ten week storage.

    Sproul and Sivyer (1976) investigated the use of diphenylamine dips,
    prior to fumigation with methyl bromide, to prevent phytotoxic damage
    from the fumigation.  They showed that fruit dipped in diphenylamine
    baths containing 250 mg/L to 1,000 mg/L were completely free of any
    injury following fumigation.  The residues in such fruit ranged from
    0.6 mg/kg to 1.9 mg/kg after three weeks in cold storage.  Rippon
    (1977) reported the results of one trial in which apples were treated
    in baths containing 1,000 mg/L and 1,250 mg/L of diphenylamine.  The
    residues resulting from such treatment ranged from 0.36 mg/kg to 0.86
    mg/kg on the whole fruit.



        Table 5.  Diphenylamine Residues on Apples following Different Treatments and Storage Times 
    (USDA Data)

                                                                                                      
    Treatment     Storage       Variety                      Diphenylamine Residues
                   Time                      Value       Surface          Pulp            Total
                                                                                                      
                                             Number      2                2                 0
    None           None        Delicious     Range       0.02-0.03        0.23-0.29         -
                                             Mean        0.03             0.26              0.29+
                                             Number      5                2                 0
    None           None        Winesap       Range       0.01-0.07        0.28              -
                                             Mean        0.03             0.28              0.31+
                                             Number      4                4                 2
    1000 ppm       1 day       Winesap       Range       4.2-5.1          0.9-1.0           -
    (42% WWP)                                Mean        4.3              0.9               5.2
                                             Number      4                4                 1
    1000 ppm       2 mo.       Winesap       Range       1.5-1.7          1.8-2.4           -
    (42% W)                                  Mean        1.6              2.2               3.8
                                             Number      4                3                 1
    1000 ppm       9 mo.       Delicious     Range       0.16-0.20        0.40-0.42         -
    (42% WWP)                                Mean        0.18             0.40              0.48
                                             Number      4                4                 1
    1000 ppm       9 mo.       Delicious     Range       0.23-0.27        0.24-0.29         -
    (50% Emul)                               Mean        0.25             0.26              0.51
                                                                                                      

    *  Total residue in these instances was calculated by addition of amount found on surface and pulp.
    


    Table 6. Effect of Formulation on Diphenylamine residues on single,
    whole McIntosh apples resulting from Dipping. (Residues immediately
    after Treatment but treated after storage)

                                                 
      Actual
    DPA applied    Formulation       DPA residues
        ppm                               ppm
                                                 

       1000          alcohol               1.7
       1000          alcohol               2.2
       2000          alcohol              17.6
       1000          42% DW*               2.1
       1000          42% DW                0.8
       2000          42% DW                1.1
       2000          42% DW                0.4
       3000          42% DW                3.3
       2000          84% DW                2.3
       2000          84% DW                1.8
       3000          84% DW                1.6
                                                 

    * DW = dry wettable. (See Cornell, 1962).  Analytical method of 
    Bruce et al, (1958).


    Table 7.  Effect of Formulation on Diphenylamine Residues on 20 Apple
    Samples of whole McIntosh Apples resulting from Dipping. (Residues
    immediately after treatment)

                                                       
      Actual                             DPA residues
    DPA applied    Formulation       Avg. of two samples
                                                       

       1000          alcohol                   3.0
       1000          alcohol
       2000          alcohol                   5.6
       2000          alcohol
       3000          alcohol                   6.0
       3000          alcohol
       1000          84% DW                    0.6
       1000          84% DW
       2000          84% DW                    1.8
       2000          84% DW
       3000          84% DW                    2.1
       3000          84% DW
                                                       

    See Cornell, 1962. Bruce et al (1958).



        Table 8.  Diphenylamine Residues on Whole Apples with Dry Wettable formulation (Residues Immediately
    after treatment* at Harvest time).

                                                                                                     
    Analytical               Actual          Active      Variety            DPA residues (avg. of 2
    Method                    DPA          Ingredient                       corrected for control
                          applied, ppm         %                                     ppm
                                                                                                     
                                                         By dipping
    Bruce et al  (1958)      2000             42           Cortland                   3.0
      "            "         2000             42             "
    Harvey et al (1959)      2000             42             "                        2.7
       "           "         2000             83         R.I. Greening                1.9
       "           "         2000             83             "
       "           "         2000             83             "                        1.4
       "           "         2000             83             "
       "           "         1000             83           McIntosh                   1.6
       "           "         1000             83             "
       "           "         1000             83           Cortland                   2.2
       "           "         1000             83             "
       "           "         2000             83             "                        3.9
       "           "         2000             83             "
                                                       By Crate Sprays
    Bruce et al (1958)       2000             42           Cortland                   8.5
       "           "         2000             42
    Harvey et al (1959)      1000             83           McIntosh                   2.3
       "           "         1000             83             "
       "           "         1000             83           Cortland                   2.3
       "           "         1000             83             "
       "           "         2000             83             "                        4.7
       "           "         2000             83             "
                                                        Box Immersion
    Harvey et al (1959)      1000             83           McIntosh                   2.0
       "           "         1000             83             "
       "           "         1000             83           Cortland                   3.0
       "           "         1000             83             "
                                                                                                     

    Apples frozen in sealed poly bags until time of analysed.  First box dipped in 1 gallon of 2000 ppm
    DPA.  16th box dipped in 1 gallon of 2000 ppm DPA.  Recoveries 70 -95%
    


    Allen et al (1979) reporting on-going studies in the United Kingdom
    indicated that the deposit on Bramley apples increased with increasing
    dip concentration (Table 9).  The initial concentration deposited from
    the unusually high dip concentration of 1,000 mg/L was 6 mg/cm2
    (approximately 6 mg/kg).

    Table 9. Effect of dip concentration of residue deposit

                                                      
    Dip concentration      Mean initial deposit (S D)
          (ppm)                    (g cm2)
                                                      
           500                     1.32  (0.25)
          1000                     2.27  (0.42)
          2000                     3.62  (0.89)
          4000                     6.01  (1.26)
                                                      


    The levels after 5 months' storage were less than 0.25 g cm2 and
    after nine months storage, less than 0.01 g cm2, from all
    concentrations of dip solution.

    For Bramley apples, an amount per unit area (g cm2) is approximately
    equal to the whole fruit concentration (ppm or mg/kg).  Further work
    is in progress to determine if deposits or efficacy vary between two
    commercial formulations of DPA when applied in the laboratory. 
    Similar work, with one of these formulations, was carried out under
    commercial conditions on farms in 1977, and is being repeated in 1978.
    Preliminary work suggests that problems may arise if DPA dip solution
    is mixed with certain other chemicals.

    Extensive investigations carried out in Australia over three years
    (Snelson, 1979) in which apples from 88 packing houses were analyzed
    for diphenylamine residues, reveal that only 1% of the samples
    contained residues above 3 mg/kg when examined after approximately 8
    weeks in cold storage.  The distribution of residues is indicated in
    Table 10.  It will be noted that 86% of the residues in whole fruit
    are at levels below 1 mg/kg.  99% of the samples contained less than 3
    mg/kg, notwithstanding the fact that in some samples the peel
    contained more than 20 mg/kg of diphenylamine.

    Table 10. Distribution of Diphenylamine Residues in Australian Apples

                                                                          
                PEEL                                   WHOLE FRUIT
                                                                          
    Range of                                Range of
    Residue       No. of       %            residue      No. of         %
    Levels        samples                   Levels       samples
                                                                          

       1.0          10        11               0.1           8          9
    1.1 - 2.0       14        16             0.1-0.5        46         52
    2.1 - 5.0       27        31             0.51-1.0       22         25
    5.1 -10.0       28        31             1.1-2.0         7          6
    10.1-20.0        5         6             2.1-3.0         5          6
       20            4         5               3.0           1          1
                                                                          
    Total           88       100                            88        100
                                                                          

    Snelson (1979)


    METHODS OF RESIDUE ANALYSIS

    No new information has become available on improved analytical
    techniques.  The Ad Hoc Working Group on Methods of Analysis of the
    Codex Committee on Pesticide Residues has recommended that the method
    published in Pesticides Analytical Manual, Volume 2, US Food and Drug
    Administration, Washington DC, USA (1977) is suitable for regulatory
    purposes and should be used for the determination of phenylamine
    residues on apples.  It should be recognized that since the bulk of
    the residue is in the peel, it is not necessary to process the whole
    fruit.  The peel may be removed and processed for analysis so long as
    the ratio of peel to whole fruit is determined on each sample.  The
    considerably higher concentration in the peel greatly facilitates the
    cleanup and quantitation steps.

    NATIONAL RESIDUE LIMITS REPORTED TO THE MEETING

    The meeting was made aware that national governments had proclaimed
    the following maximum residue limits:

                                       
    Federal Republic of Germany     3
    Netherlands                     3
    Sweden                          3
    United Kingdom                  3
                                       

    APPRAISAL

    Following the recommendations of the 1976 Meeting and a request from
    CCPR, the available data on residues on apples has been reviewed and
    the results of additional surveys and trials have been made available.

    Although some results from supervised trials made in 1961 suggest that
    residues could reach levels of the order of 10 mg/kg, later data
    suggest that, in some cases, the higher and variable residue levels
    obtained at that time were due to the use of formulations which have
    since been replaced by preparations which do not separate in dip
    baths.

    The meeting was aware that following normal treatment in packing
    houses, the residue level in some treated apples could exceed 5 mg/kg
    for a few days, but this is of little practical consequence since
    treated fruit is usually not presented for sale immediately. 
    Treatment is normally only applied to fruit going into cold storage
    and even minimum storage results in a significant decline of
    diphenylamine residues from the skin surface.  At room temperature,
    the surface deposit disappears in a few days.

    The meeting agreed that there is little justification for retaining
    the maximum residue limit at the value of 10 mg/kg established in
    1969.  Available information indicates that a MRL of 5 mg/kg is
    adequate to deal with residues in apples in commerce, resulting from
    typical levels and methods of treatment especially if the period
    between application and release into trade is 21 days or more.

    Use patterns and application practices appear to have changed since
    the early 60's when the data considered at the 1969 meeting were
    generated.  The meeting requested further information on current
    practices and residues resulting therefrom from countries where higher
    MRLs have been established.

    RECOMMENDATIONS

    The meeting recommends that the existing maximum residue limit of 10
    mg/kg for diphenylamine on apples should be lowered to 5 mg/kg.

    FURTHER WORK OR INFORMATION

    Desirable

    Information on current practices, formulations, use patterns and
    selective surveys of residues in crops known to have been treated
    under practical circumstances.

    REFERENCES

    Allen, J.G., Hall, K. L., Martin, S., Sharples, R.O. and Johnson, D.S.
    Diphenylamine for scald control. Rep. E. Mathing Res. Sta. for 1978.
    p. 114.

    Bruce, R.B., Howard, J.W. and Zink, J.B. - Determination of
    diphenylamine residues on apples. J. Agr. Food Chem. 6: 597-600.

    Denmead, C.F., Vere-Jones, N.W. and Atkinson, J.D. - A commercial
    method of controlling apple scald with diphenylamine emulsions. J.
    Hort. Sci. 36: 73-84.

    Cornell University - Diphenylamine residues on apples. Information
    supplied to US Food and Drug Administration February 26, 1962.

    Ginsberg, L. - Superficial scald and its control on South African
    apples. The Deciduous Fruitgrower Feb. 1962 pp. 34-41.

    Gorman, R.C. and Rowe, N.B. - Investigation into the preparation,
    stability and effectiveness of apple dipping emulsions of
    diphenylamine. Report to Pesticides Co-ordinator August 1977 from
    Western Australian Government Chemical Laboratory.

    Hall, E.G., Scott, K.J. and Cook, G.C. - Control of superficial scald
    on Granny Smith apples with diphenylamine. Aust. J. Agric. Res 12 (5):
    834-853.

    Hanekom, A.N., Scheepers, J.L. and DeVilliers, J.F. - Factors
    influencing the uptake of diphenylamine by apple fruit. The Deciduous
    Fruitgrower, October 1976 pp. 402-411.

    Hardisty, S.E. - Bitter pit control could save export Granny Smith
    apples. J. Agric. W.A. p. 28-30.

    Harvey, Helen and Clark, P.J. - Diphenylamine residues on apples. NZ
    J. Sci. 2: 266-72.

    Little, C.R. - Post-harvest treatment for pome fruit - some practical
    implications.  Proceedings of Fruit and Vegetable Post-Harvest
    Research Workshop, Glenelg, South Australia, Sept. 1977 pp. 140-145,
    CSIRO Canberra, Australia.

    Luke, B. - Diphenylamine residues on apples.  Report to Australian
    Government Analyst, 28 July 1978.

    Rippon, L.E. - Pesticide residues in fruit resulting from post harvest
    treatments: Proceedings - Fruit and Vegetable post-harvest Research
    Workshop, Glenelg, South Australia, September 1977.  CSIRO, Canberra,
    Australia.

    Snelson, J.T. - Diphenylamine residues in apples. Report from Dept. of
    Primary Industry, Canberra, 12 October 1976.

    Sproul, A.N. and Sivyer, M. - Residues resulting from the use of
    diphenylamine to reduce injury from methyl bromide. Report to Fresh
    Fruit Disinfestation Committee from Western Australian Department of
    Agriculture.

    Sproul, A.N., O'Loughlin, J.B., Terands, A., and Hardisty, S. - The
    use of diphenylamine to protect apples from methyl bromide injury.
    Aust. J. Agric. Res., 27, 541-5.

    USDA - Determination of diphenylamine residue in apples. Report by the
    Handling, Storage and Transport Investigations Unit, Agricultural
    Marketing Service, U.S. Department of Agriculture, Wenatatchec,
    Washington (September 1961) to US Food and Drug Administration.
    


    See Also:
       Toxicological Abbreviations
       Diphenylamine (ICSC)
       Diphenylamine (FAO/PL:1969/M/17/1)
       Diphenylamine (Pesticide residues in food: 1976 evaluations)
       Diphenylamine (Pesticide residues in food: 1982 evaluations)
       Diphenylamine (Pesticide residues in food: 1984 evaluations)
       Diphenylamine (Pesticide residues in food: 1984 evaluations)