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FIGURE 1. Beneficial insects are always on the lookout for a good home! Gardeners can “advertise” the suitability of their home real estate in a variety of ways.

   
 

 

FIGURE 2. Pictured above is a view of our demonstration garden at the Galveston County Extension Office. In general, the greater the diversity in types of plants in a landscape, the more likely that diverse types of beneficial insects will establish "residency.

   
 

 

"FIGURE 2. Know your enemies—and your friends . . . at least a few beneficial insects are almost certainly already in your yard and garden.

   
 

 

FIGURE 4. During extended periods of dry weather, we provide a water source for beneficials in our demonstration garden located at Carbide Park in La Marque, Texas.

   

The use of beneficial insects to help manage their pest relatives has been a mainstay among gardeners for a very long time. There are a number of excellent advantages to this method of control:

• Requires a minimum of effort by the gardener.
• Helps prevent the development of pesticide resistance in target insects.
• Does not contribute to environmental pollution.
• Aids in maintaining a more natural balance in our ecosystem.
• Beneficial insects can often keep pace with pest populations.

We gardeners can attract and keep our natural friends in our backyards and gardens by following these suggestions, many of which are just good gardening sense that we use anyway.

PREVENTION: A STITCH IN TIME . . .
Using good horticultural practices goes a long way to help prevent and/or minimize pest infestations. As much as possible, use disease resistant plant varieties. Keep your plants healthy by providing appropriate moisture, drainage, and air circulation.

Dispose of severely diseased plants immediately by putting them in a plastic bag in your regular garbage, not in the composting bin. Avoid placing plants in the wrong areas by consulting other horticulturists about what species and varieties thrive in sites with poor drainage, compacted soil, or in other less-than-ideal locations.

Mulch properly, remembering to pull mulch back a little from the base of trees. Avoid improper fertilization by having the soil tested to see what and how much amendment it really needs. Adding more than the needed amount of nutrients can backfire; for example, too much nitrogen can actually encourage aphids and mites more than it helps the vegetation.

IF YOU FEED THEM, THEY WILL COME . . .
The adults of many beneficial insects, such as bees, ladybeetles, hover flies, parasitic wasps, etc., feed on the nectar and pollen produced by flowering plants. Including such plants in the garden will help ensure that these friends will stick around long enough to lay their eggs on your vegetation.

Then, the larvae will consume aphids, caterpillars, cutworms, thrips, and mites, among other bad guys. Plants that are the most attractive to beneficials are those with small flowers arranged in clusters. Families with these characteristics include:

Carrot (Apiaceae)—dill, parsley, fennel
Asters (Asteraceae)—asters
Mustard (Brassicacea)—sweet alyssum, nasturtium, candytuft
Daisy (Compositae)—coneflowers, yarrow, daisies, goldenrod

The flowers of these plants provide easily accessible nectar and a good landing strip.

Provide a continuous food supply by choosing a variety of plants that bloom at different times during the growing season. Early bloomers include alyssum and pansies while late bloomers are goldenrod, sedum, and asters.

Also, water your crawlers and fliers along with your vegetation. During extended periods of dry weather, place a sufficient amount of small rocks or gravel in a bird bath to provide them a foot pad from which to "drink" safely.

THEY’RE JUST LOOKING FOR A GOOD HOME…
Like any living thing, insects need shelter. We can provide suitable shelter by leaving some leaf litter in landscape beds and/or by periodically replenishing mulch in landscape beds to give ground-dwelling allies a place to hide when they need to. Ground cover plants can provide not only a home but pollen, nectar, and prey for some types of predators and parasitoids.

Places such as fence rows and windbreaks can also act as a haven for friendly insects. In general, the greater the diversity of plants in a landscape, the more likely that diverse types of beneficial insects will establish "residency."

KNOW YOUR ENEMIES—AND YOUR FRIENDS . . .
Beneficial insects are almost certainly already in your yard and garden. Before using any pest control strategy, it is vital to identify accurately what is REALLY causing the problem and what will REALLY remedy it. County extension personnel, reference books, fact sheets, computer resources, and other horticulturists can assist in this process.

Inspecting your plants about every two weeks will go a long way in preventing and controlling enemy invasions. Frequent inspections will enable you to find pests while they are still small or immature and not quite so numerous. Catching them early often results in the use of non-toxic of less toxic methods of control. Look for the friendly fellows, too. You may discover that they are already providing all the control that your plants need.

CONSERVE, PRESERVE, PROTECT . . .
Besides providing shelter and food, there are other ways to ensure that beneficials continue to work for your garden’s benefit. Use non-chemical controls when possible, including pruning, hand-picking, covering plants with netting, etc.

If pest populations are overwhelming beneficials, consider augmenting them by purchasing and releasing more beneficials. Once again, education is the key to success. Learning which insects will be the most effective, when to release them, and how to maintain them before and after release are crucial to achieving control objectives. Also, avoid the used of bug zappers. Studies have shown that they kill more desirable insects than pests.

USING CHEMICAL CONTROLS . . .
There are many valid reasons for using chemical controls: excessive plant damage, time constraints, and economic impact are among the many factors to consider. Because of potential environmental and personal consequences, the appropriate, safe use of insecticides and other types of pesticides cannot be overemphasized.

Know the product. Read the label. What does it kill? On which plants is it safe to use? It is illegal to used a chemical control for insects and on plants that are not listed on the label. Such use can harm the plant and may not kill the target insect. Use only the amount and only as frequently as directed on the label.

Use the least toxic chemical that will achieve the goal, such as horticultural oils and insecticidal soap. Choose selective insecticides that are toxic to a specific pest and are not directly harmful to beneficials. Bt (Bacillus thuringiensis) for the control of mosquitoes is a good example.

Remember that beneficial insects are still insects. Broad spectrum insecticides that wipe out a wide variety of pests will almost certainly impact friendly critters, too.

Use selective application. This includes spot spraying and rotating areas of spray.

SUMMARY . . .
Relying on beneficial insects as a pest control method is not a matter of sitting back and “letting nature take its course.” As with any other effective gardening tool, it requires education, effort, patience and awareness. We may need to give up some ideas about the perfectly groomed yard and become willing to tolerate a certain amount of insect harm. Most plants can put up with some damage without too much ill effect. The pay-offs of observing and participating in a more naturally balanced ecosystem can be well-worth the effort.

Beneficials in the Garden & Landscape is an EarthKindTM program coordinated through Extension Horticulture at Texas A&M University. Earth Kind uses research-proven techniques to provide maximum gardening and landscape enjoyment while preserving and protecting our environment.

 

This web site is maintained by Master Gardener Laura Bellmore, under the direction of William M. Johnson, Ph.D., County Extension Agent-Horticulture & Master Gardener Program Coordinator.

All digital photographs are the property of the Galveston County Master Gardener Association, Inc. (GCMGA) © 2002-2008 GCMGA - All Rights Reserved.