Not Every Insect Needs to be Killed

March 17, 2017

by Larry Williams

Be careful to not overuse pesticides.

Pesticides are good tools when used properly. But overuse of pesticides in our lawns, landscapes and gardens can result in a number of problems.

Insects can become resistant to insecticides when a product is repeatedly used. Because many insect species reproduce rapidly, having many generations per year, a resistant population can develop in a short time. We’ve seen this happen in agriculture and in landscapes. Hundreds of insect species are known to have resistance to certain insecticides. The end result is an insect population that can no longer be easily controlled.

The ladybug is one of the beneficial insects killed by insecticides.

Pesticide overuse can make some pest problems worse. For example, the insecticide carbaryl (Sevin) will kill many insects but will have little or no effect on aphids or spider mites. And repeated use of carbaryl will eliminate many beneficial insects that feed on these pests. So you may end up with much larger populations of aphids and spider mites than if you applied no insecticide at all.

Indiscriminate use of broad-spectrum pesticides such as malathion, pyrethrum and carbaryl kill many insects, good and bad. Not all insects need to be killed. Less than one percent of all insects in Florida are damaging to plants and many are beneficial. These beneficial insects are the “good guys” of the insect world. They feed on harmful insects. And, as a result, help keep their numbers in check. Once you’ve made the mistake of killing off the good guys, such as lady beetles, you may have to increase the use of insecticides because the good guys are no longer there to help reduce the harmful insects. Conversely, if you eliminate all of the bad insects, the beneficial insects will not have anything to eat. Spraying every six-legged creature that exists is not a good idea. The overuse of pesticides can throw off the delicate, beneficial balance that exists in nature.

We need to tolerate a few pests and a little damage. Attempting to maintain a pest-free landscape is not only impractical but it is a waste of money and time and may be detrimental to the environment. And besides, the number of pesticides to choose from is becoming smaller, partly due to environmental concerns.

Pesticides are not always the best choice when dealing with pests. Instead of blanketing your landscape with pesticides, use some strategy. There are many other options such as choosing pest resistant plants, avoiding excess fertilization and watering, eliminating a plant that has to be frequently sprayed, eliminating small pest populations by hand, etc.

While pesticides remain part of our pest control arsenal, care should be taken to use them wisely and correctly.

Larry Williams, UF/IFAS Extension Agent, Okaloosa County

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