Plant Pathology Infobytes

January 20, 1998
Gardening Tips for 1998 - Dealing With Pesticide Residues

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 cabbage several times with a fungicide not approved for use on this crop. The gardener finds out this out afterwards and telephones the Extension office wanting to know: "Can I wash the cabbage heads and remove enough fungicide so 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 tomatoes, mustard or turnip greens, plums, peaches, apples, or any of the other food crops routinely sprayed for disease and insect pests by Mississippi gardeners and orchardists each season. And the pesticide involved in the mis-use application could have been an insecticide, or herbicide, just as well as a fungicide.

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 residue of a pesticide not cleared for use on the food crop in question, we respond in the following manner.

  • 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 cabbage described earlier, since the fungicide is okay to use on other food crops like tomatoes and green beans. What's the big deal? According to state and federal pesticide laws and regulations, it boils down to a legality matter, simply stated, "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 we prepare for the 1998 gardening and fruit production season, 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.

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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