Did you know that only 3% of all the insects in world are destructive? I was listening to a garden show on TV when the host asked the guest entomologist if this statement is true. The entomologist said it was. I was amazed so checked with two entomologists at the University of Nebraska-Lincoln and a County Extension Educator. They all confirmed that the statement is true.

          The host of the TV program then asked “Why, when I spray my plants with a bug killer, does it seem in a few days there are more insects than when I started spraying?” The entomologist told the host that it was probably because he not only killed the bad bugs, but also the beneficial natural enemies (predators and parasitoids) that normally keep them in check. Have you had that experience?

In Part #1 of this series I wrote about the identification of weeds in your lawn and garden. Part #2 was about using the right product to control those unwanted plants. Part #3 will be about identification of insects and Part #4 will be about using the right product, at the right rate, at the right time to control insects.

It really bothers me when people get out the bug spray whenever they see any kind of insect. Or when people buy a 4-step, 5-step, or 6-step lawn program and put an insecticide on their lawn even though they do not have an insect problem, or not sure they have, or put it on in hopes they do not get one.

          I overheard a man tell a store clerk that he had just finished mowing his lawn and had many moths fly up as he mowed. He was sure they would destroy his grass. He asked for an insecticide that would take them all out. He had no idea what the moths were and if they would injure his lawn.

          For years the only insecticide I have put on my lawn is “Merit” for grubs. The more insecticide you use the more you kill the beneficials and predators that keep the bad bugs under control. Don’t use an insecticide (liquid or granular) unless you have to, and then use the least toxic insecticide to get the job done. Remember that those all summer, season long insecticides kill as many beneficials as they do harmful insects.      

          One entomologist told me that the other 97% of the insects can probably be classified as follows:

1.       Nuisance insects-- A good example is the Boxelder Bug. This bug does not eat your plants, and it does not bite you. When it gets into your home it does not eat clothes, drapes, or furniture. These bugs are just a nuisance and can be best cleaned up with a vacuum. Mini-vacs are a tremendous advance in household pest control technology. And no chemicals are needed. Most people do not like these nuisance insects but they are not destructive.

2.       Neutral or incidentals-- They exist in our environment but are not chewing on our plants, they do not transmit diseases, nor do they bite us or our pets. Some, like butterflies, can be very pretty and are prized for their aesthetic value.

3.       Beneficials-- They can be further classified as:    

·        Decomposers, that break down organic matter, help turn yard and kitchen scraps into compost, and are necessary for the health of the soil in our yard and garden;

·        Pollinators, such as bees, flies, beetles, and other flower-visiting insects;

·        Predators and parasites, including lady beetles, green lacewings, syrphid flies, ground beetles, parasitoid wasps, and other insects that eat aphids, grubs, caterpillars, as well as other yard and garden pests. The parasitoids lay their eggs in, on, or near many undesirable insects, their eggs eventually hatching and the larva feeding on the host insect, soon killing it.

          Whitney Cranshaw, Colorado State University entomologist, has written an article on “Beneficial Insects and Other Arthropods”. In this article he describes a number of the beneficial insects and the other insects they go after. He also has a section on “The Use of Flowering Plants by Beneficial Insects”. Adult lacewings, flower (syrphid) flies and parasitic wasps, for example, feed on flower nectar and pollen. Their young devour many of the insect pests that can make a gardener’s life miserable. Maintaining this workforce however means providing food for the beneficials and tolerating a few insect pests. For a copy of this article go on the internet to  For related articles from Colorado State Extension go to Here you will find a whole list of good yard and garden articles.

           There are a number of choices on how to control your garden pests. These include biological control, cultural control, mechanical control, and chemical control.    In Part #4 more about insects, more about your choices for control, a list of references, and I will especially encourage you to Use the right insecticide, at the right rate, at the right time, on the right insect.

Copyright 2011