Did you know that there are over 1,000,000 insect species that have been described by entomologists? Do you know how many of these are actually garden pests? According to a University of Wisconsin Extension Horticulture Educator, less than 100 are actually garden pests. As reported last week, only 3% of all insects are destructive and not all of the bad insects are found in the garden. The other 97% of the insects can probably be classified as follows:

·        Beneficials

·        Nuisance insects

·        Neutral or incidentals

         Integrated Pest Management or IPM is an approach in which you first identify the insect on your plant, and then apply the least invasive treatment possible at the correct time, but only if the insect is actually damaging your plant. If you think you have a problem, go to the local County Extension Office, a full service garden center, or other expert for an accurate diagnosis and informed recommendation. There are a number of choices on how to control your garden pests. These include biological control, cultural control, mechanical control, and chemical control.

·        Biological control involves the introduction and conservation of natural enemies including predators, parasitoids, and pathogens to suppress insect pest infestations. This approach includes applying an insecticide only when it will be most effective, and as selectively as possible, so as to promote the natural activities of the beneficial insects.

·        Cultural control is selecting plants that are less prone to serious insect problems. Also, it means practicing good sanitation in your garden as many insect pests can overwinter in plant debris, and using proper watering, fertilizing, and good growing practices so you have healthy plants.

·        Mechanical control is a great option and includes physically preventing certain insects from attacking your plants. Nets (row covers) over plants during periods of high pest activity and physically removing the insects and destroying them avoids chemical use.

·        Chemical control should be used only when needed and only as one component of your insect management plan. Remember, insecticides need to be used properly and always follow the instructions.

If you use a general purpose insecticide like Sevin, Eight, Malathion or bifenthrin every time you see a bug, you may be doing more harm than good. Make sure there are insects present that are actually hurting a plant before spraying, and then Use the right insecticide, at the right rate, at the right time, on the right insect.

         What is the right insecticide? Do you know that Sevin does not work very well on aphids, but is highly toxic to the ladybugs that eat aphids? Sevin is also highly toxic to bees that pollinate your flowers, cucumber, squash, and many other plants. Also, grubs can be very destructive to a lawn but some chemicals are better than others, and the wrong chemical, at the wrong time will not cure the problem or prevent damage to the lawn. Grub control put on too early, or not watered in, becomes ineffective and is not available in the top 2 to 3 inches of the soil when needed. In Eastern and Central Nebraska the grubs in your lawn come from masked chafer (June) beetles. They lay their eggs in July and these eggs start to hatch out around the first of August. Merit (Fortify or Bayer Advance) or Mach 2 (Scotts Grub Control) should be applied from mid to late July and should be thoroughly watered in with at least ½ inch to ¾ inch of water. These products when properly used will protect your lawn for the rest of the summer.

         Dylox and other short residual insecticides will kill grubs but need to be applied in August after the eggs have hatched and when the small grubs are present. Again, adequate irrigation after treatment is essential for acceptable control. Remember, the bag may say the product inside will kill grubs, but not specify how well and usually does not say when to apply IN NEBRASKA. Some chemicals get tied up in the thatch and never reach the grubs which are feeding below the soil surface. Milky spore is advertised as an organic control of grubs. It does work on Japanese Beetle larvae, but is of little value in Nebraska and the Midwest where our primary species is the masked chafer grub.

         When controlling aphids I use insecticidal soap first as this product does not injure the beneficial predators (lady beetles). Insecticidal soap is also good for use on spider mites and many other destructive insects. It can be used in the vegetable garden up to the day of harvest. Use the right insecticide, at the right rate, at the right time, on the right insect.

         People have asked me, “When is the right time of day to spray?” Pollinators, and many beneficial insects, are most active in the morning. They go back to the hive or nest about noon and avoid the heat of the day. The best time to apply an insecticide, therefore, is in the evening after most beneficial insects have gone to bed. If you have fruit trees, or nut trees that need insects for pollination, do not apply fruit tree spray when the trees are in bloom or you will destroy most of the pollinators. The flowers attract the pollinators and spraying during this time period is very destructive. 

          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”. For a copy of this article go on the internet to

Copyright 2011