Plant Pathology Infobytes

August 2, 1999
Dealing With Illegal Pesticide Residues on Food Crops

Over the course of the gardening season, County Extension Offices receive numerous questions dealing with pesticide use and food safety. This is a good sign because it indicates gardeners and orchardists realize pesticides can present health risks if not used in a safe and responsible manner.

The following is a typical pesticide use situation faced by County Extension personnel each season. A vegetable gardener sprays his tomato crop several times with a fungicide (or insecticide) not approved for use on this crop. The gardener finds out later the pesticide was not cleared for use on tomatoes and checks with the Extension office wanting to know: "Can I wash the tomato fruit and remove enough of the pesticide so that it's safe to eat?"

Unfortunately, the answer we would have to give is "No" for the reasons explained later in this article.

The crop could just as easily have been squash, cucumbers, lima beans, orchard crops such as apples, grapes, peaches, or any of the other food crops routinely sprayed for disease and insect pests by Mississippi home vegetable gardeners and orchardists each season.

In most cases home gardeners and orchardists use the appropriate fungicide or insecticide and there is no question about legality of the application and resultant pesticide residue. However, what if a fungicide or insecticide is applied to a fruit or vegetable crop not listed on the pesticide label?

When the County Extension Office receives questions about the advisability of consuming fruits or vegetables containing a residue of a pesticide not cleared for use on the food crop in question, our response of "don't eat it" is based on the following facts:

  • The food crop would contain an illegal pesticide residue; therefore, the fruit or vegetable in question should not be consumed.
  • Washing produce, or waiting a period of time until the produce is "safe" will not correct the situation. Washing helps, but no amount of washing will remove all illegal residues which may be present.
  • Common sense suggests that harmful health effects probably wouldn't result from eating the tomato fruit described earlier, since the fungicide is okay to use on other food crops. So, what's the big deal? According to state and federal pesticide laws and regulations, it boils down to the fact that "Food crops containing illegal pesticide residues should not be consumed." Therefore, the County Extension Office cannot tell you that its okay to consume fruits or vegetables which could contain such residues.
  • As you prepare for the fall gardening season, and future vegetable and fruit crops, the best advice we can give you is "Read the pesticide label and strictly adhere to the use directions it contains." And one of the key pieces of information determine is to make sure the pesticide product is cleared for use on the crop you're thinking about using it on.

If you have doubts about the safe use of any pesticide product, never hesitate to call the County Extension Office, but don't forget, its best to call with "before use" and not "after use" questions.



Written by the late Dr. Frank Killebrew

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