Good, Bad, or Just a Nuisance?
by Nanette Londeree, Master Rosarian
The more insects you have in your garden, the fewer insect problems you will have. This seems like a contradiction, but in a healthy garden ecosystem, beneficial insects far outnumber harmful ones.
There has been a big shift in commercial agriculture over the past few decades to get away from the use of pesticides and utilize insect predators in order to control pest populations. This is not a new thing. The use of insects for biological control dates back to at least the fourth century A.D. when ants were manipulated to control citrus pets in China. Insect predators, in the immature and often adult stages, feed directly on their prey, killing them immediately.
The advent of chemical pesticides in the 1940’s seemed to promise pest-free garden’s, but by destroying good as well as bad bugs, it disrupted the workings of nature and eventually increased pest problems. Today we are learning that even botanical pesticides should be used only as a last resort.
Even in monocultures such as farms, orchards and commercial greenhouse, mass reared beneficial insects can be released to control pests as they appear. In more diversified plantings such as gardens, we can easily build up native populations of beneficials so that all but the occasional massive pest outbreak can be controlled without potent chemicals.
Lawn grasses provide homes for predators such as tiger, ground and rove beetles, while native grasses are winter harbors for ladybugs, assassin bugs and other beneficials. Try to ensure a steady supply of food for predators and parasites by growing the widest possible variety of flowers all season. Many predatory and parasitic insects need nectar and pollen from flowers for nourishment in order to lay eggs. Umbelliferous plants are especially helpful because they have tiny flowers with exposed nectar that is easily reached by small beneficials, and composite flowers like daisies that have easy to reach pollen centers.
Getting to know the creatures that inhabit your garden is important as some are beneficial, some can be very destructive and some are just a plain nuisance. There are well known beneficial insects such as bees, butterflies and lady bugs, and not so well known critters like the assassin bug, the big-eyed bug and the soldier beetle. Over the next few months we will introduce you to some of these little known heroes, as well as some of the garden fiends to watch out for.
Assassin bugs (see photo above), in the family Reduviidae are general predators that feed on a variety of insects including aphids, leafhoppers, caterpillars, fly larvae and bed bugs. Like all true bugs, regardless of host, they feed by needle-like sucking mouthparts with which they drain the juices from their host (be it sap or blood). The assassin bug is about ¾ – 1 inch long with an elongated head that is often tilted upward. A long beak project from the front of the head and curves under the body. They are light brownish-green to dark brown.
Assassin Bug Photo by: W. L. Sterling, courtesy of:
Department of Entomology, Texas A&MUniversity