Activist groups have expressed concern about the fungicide diphenylamine (DPA), an important and widely used tool by the apple industry for post-harvest storage.

  • DPA was first registered as a pesticide in the U.S. in 1947.  The EPA has reviewed DPA’s registration several times (1991, 1996, 1998, and 2018). As part of the most recent review that began in 2018, the Agency accepted public comments through March 21, 2019.
  • DPA is commonly used and is essential in the apple industry’s post-harvest control of scald (browning) on apples. Currently, DPA is the only registered pesticide available for post-harvest treatment on apples that provides effective control of scald. Other chemicals have been tested and although they reduce scald, they have not been as effective as DPA. Storage scald is one of the most economically serious post-harvest disorders of apples, so it is vital that it be controlled. 
  • The results of this registration review are of great importance to the apple industry.  All apple varieties are susceptible to scald which means that the loss of the only tool available will have a large negative economic impact and result in increased food waste and reduced availability of a healthy food when supplies are dwindling.  
  • The latest data from USDA’s Pesticide Data Program (2016), which analyzes a wide variety of produce for pesticide residues, found that the average for apples where DPA was detected to be 0.283 parts per million.  The EPA tolerance for DPA on apples is 10 parts per million, which means that the average of all DPA detects was more than 97 percent below the EPA tolerance. (See the chart below from the 2016 USDA Pesticide Data Program Report)
  • In the September 1997 re-evaluation of the registration for DPA and associated tolerances, EPA found that the registration and tolerances met the statutory standard of reasonable certainty of no harm. The Agency also stated “DPA has been evaluated for potential carcinogenic activity in mice and rats. It is classified as ‘Not Likely’ in reference to carcinogenicity-based lack of evidence.” (
  • Loss of this valuable tool would result in increased food waste, lower availability of a high-quality food to consumers, and serious economic impacts from losing sales in domestic and international markets.