The Effects on Spraying Insecticides on Fruits & Vegetables

It’s tempting and easy to attack the insects that attack your fruit and vegetables with insecticides. Insecticides are classed together with herbicides in the general category of pesticides. The University of California at Davis website defines a pesticide as, “any material used to control, prevent, kill, suppress, or repel pests.” This site suggests that gardeners learn about the product they intend to use and evaluate whether a natural remedy might solve their pest problem.

Destructive Insects

Insecticides kill destructive insects. However, before using an insecticide, identify the type of insect that is the problem, and then choose an insecticide that will best target that insect. The University of California at Davis website recommends that gardeners purchase a chemical insecticide product effective, yet as nontoxic as possible to your health and its effects on the environment. They go on to suggest contacting your Cooperative Extension Service for their recommendations. If you have just a few nuisance bugs, you might be able to hand pick them or use a soap spray to get rid of them.

Beneficial Insects

A side effect of using an insecticide on your fruit and vegetable plants is that it does not discriminate. Although some insecticides are designed to target specific insects, many will kill all of the insects in an area. These include beneficial insects such as ladybugs, predatory wasps and lacewings, which feed on other detrimental insects, such as aphids. When the beneficial insects in your yard are reduced in number, the problems you were experiencing with destructive insects can escalate, leading to the need for more insecticide.


When humans and animals consume insecticides, they can experience negative health effects. Breathing insecticide fumes or if it comes into contact with your skin, can irritate mucus membranes, lungs and skin, sometimes seriously. A 1965 study published in the Journal of the Canadian Medical Association reported that 441 apple growers showed that “chronic intoxication by organic phosphate and chlorinated hydrocarbon insecticides” might cause negative health effects in humans. The Journal article confirmed that “practically every known insecticide” has been implicated in accidental and occupational poisoning around the world.


Although the United States banned DDT in 1972, it nearly caused the extinction of some bird species, especially pelicans, because exposure to it caused their eggs to form with thin shells. DDT was used to control mosquitoes in many municipal regions before its ban. However, in tropical parts of the world where malaria is a serious problem, DDT continues to be legal on a provisional basis. Although products for home use that contain chemicals such as malathion continue to be legal, insecticides are poisons and you should always use them cautiously and follow label instructions carefully.

Stunt Plant Growth

The website Greenhouse Grower reports on the results of a study of gerbera daisies in commercial greenhouses where chemical insecticides were used. Many insect pests that attack gerberas in greenhouse conditions include “aphids, broad mites, spider mites, whiteflies, leaf miners and…western flower thrips.” This has made the application of insecticides common in such situations. However, one of the products tested, Orthene Turf, Tree and Ornamental Spray 97, caused a reduction in the number of flowers and leaf damage that caused “yellow spotting and brown, dry leaf margins.” Another product, Triact 70, was shown to reduce photosynthesis and the production of flowers. In general, this product retarded the growth of gerberas in the study.

Keywords: insect control, insecticide chemical, dangers health environment

About this Author

Barbara Fahs lives on Hawaii island, where she has created Hi'iaka's Healing Herb Garden. Fahs wrote "Super Simple Guide to Creating Hawaiian Gardens," and has been a professional writer since 1984. She contributes to Big Island Weekly, Ke Ola magazine, GardenGuides and eHow. She earned her B.A. at UCSB and her M.A. from San Jose State University.