WASHINGTON (AP) _ A farm chemical trade association said Monday that a total ban on the use of crop fungicides would boost consumer food prices by 13 percent and reduce the supply of fruits, vegetables and peanuts by 24 percent.

Jay Vroom, president of the National Agricultural Chemicals Association, said he wanted to call attention to the ''enormous benefit and the very small risk'' that result from the use of fungicides and other high-tech farming methods on food supplies.

''In my view, the debate regarding the safety of our food is almost totally risk-dominated,'' Vroom said. ''There is precious little mentioned about the benefit side of the equation.''

An economic study showing the effects of a ban on fungicides - chemicals applied to crops, particularly fruit and vegetable, to prevent plant diseases - was released by the association at a news conference here.

The study, paid for by the association, was done by GRC Economics, a Washington, D.C., consulting subsidiary of Hill and Knowlton Inc.

The Environmenal Protection Agency's spokesman on pesticides, Al Heier, commented, ''We have always been concerned about fungicides, but we're not going to cancel all of them.'' He noted that federal law requires the agency to balance benefits against risks when judging any pesticides, and said the agency adheres to that mandate.

John M. Urbanchuk, senior vice president and director of economics for the consulting firm, said, ''If fungicides were eliminated, you the consumer would pay more for lower-quality produce. You would find that many fruits and vegetables no longer look or taste the same as before, and they would cost much more.''

For example, he said, crops hit hardest would include popular salad bar crops such as carrots, which would rise 80 percent; lettuce, 40 percent; tomatoes, 40 percent and onions, 34 percent.

Prices of other major crops also would go up sharply, he said. Peanuts and peanut butter would rise 68 percent; peaches, 37 percent and potatoes, 37 percent.

''Some foods may not be available at all,'' Urbanchuk said. ''If fungicides were no longer used by American farmers, consumers would not have bananas to slice on their morning meal, and children may not have peanut butter for their lunch sandwiches.''

Production of fruits would decline by 32 percent, vegetables by 21 percent, peanuts by 68 percent, and the major grains such as corn and wheat by 6 percent, he said.

Urbanchuck said in his statement that poorer families would suffer the most by not being able to afford higher prices for fruits and vegetables.

Lisa Lefferts of the Center for Science in the Public Interest said she had not studied the chemical industry's report and had no way to dispute the study's figures.

But, she said, the current way of growing food with large amounts of fungicides and other chemicals ''isn't the only way to do it.'' In fact, she added, the National Academy of Sciences recently reported on alternate ways of farming to reduce the contamination of soil, water and air by cutting back on chemicals.

''We're confident, and so is the National Academy of Sciences, that we can produce foods profitably and competitively using far fewer fungicides and other pesticides,'' Lefferts said in a telephone interview.

''The most telling statistic would be not how much reduced fungicide use would cost consumers, but how much it would cost the chemical industry,'' she said.

Fungicides represent about $370 million or 7.4 percent of the $5 billion-a- year farm chemicals industry, association officials said.

An advisory board for the study included representatives of the association, the National Association of Wheat Growers, National Food Processors Association, Fertilizer Institute, Resources for the Future and the Agriculture Department.