Beneficial Bugs

By DiAnne Crown

February 23, 2016 5 min read

Wait! That bug or larva you're about to spray may be a beneficial contributor to your lawn and garden. Veteran garden center manager Cara Knepler offers encouragement and caution for beginners with bugs.

*Step one is to encourage the beneficial bugs.

A healthy, biodiverse ecosystem with beneficial insects and companion plantings -- and without diseased and damaged plants -- requires less maintenance and fewer chemical interventions to control sap sucking and leaf chewing insects. Knepler's top four helpful insects are:

??Predatory mites: helpful biological control against various pest mites.

??Ladybird beetle: eats mealybugs, aphids and others.

??Hoverfly: looks like a bee, but has short black antennae. Note that the larvae eat aphids, so protect them, too.

??Praying mantis: "great against tomato hornworm and earwigs," says Knepler. "But be sure you do have some harmful insects because, if not, they'll eat anything else, including the beneficial insects, each other, anything."

Learn to recognize the life stages of these garden helpers in your region so you can protect and encourage them throughout the growing season. Look up "beneficial insects in the garden" for links to helpful websites. And for free, local advice, contact your area's master gardener or university extension office and stop by your favorite garden center.

The University of California Integrated Pest Management website offers an excellent reference, which begins, "Natural enemies are organisms that kill, decrease the reproductive potential of, or otherwise reduce the numbers of another organism. Natural enemies that limit pests are key components of integrated pest management programs." The page about hover flies for example, shows each stage in the life cycle to help you protect this important helper insect.

*Step two is to find companion planting and colorful perennials.

Companion planting both attracts pollinators and helps keep harmful insects out of your garden. For example, says Knepler, borage repels worms and attracts bees and beneficial wasps, which makes it an effective companion plant for tomatoes. Marigolds and scented geraniums do the same thing.

Knepler also likes planting sunflowers to attract aphids, which attract ants to the sugars released during aphid activity. "The insects are drawn away from other plants, but sunflowers are so tough that they aren't damaged."

In classes and conversations, Knepler emphasizes the importance of incorporating plants that attract and sustain butterflies and bees, such as Butterfly weed, Bee balm and hardy milkweed species, which provide essential habitat for our declining Monarch butterfly population. "Honey bee colonies are very stressed right now. If we don't have pollinators, we don't live." In addition, planting groups of colorful pollinators could make your garden a stop on the "Monarch Highway" and help restore this beautiful, important species.

*Step three is to see the natural controls.

When you do see evidence of harmful insects in the garden, consider natural controls first. First, remove damaged plants, which encourage infestation, says Knepler. It may be necessary to remove shoots, sections or the entire plant to control the problem. Then consider organic, topical solutions.

"When you use broad chemical controls, whether a spray or a systemic application (in the soil), you're going to get rid of all larvae, including the beneficial ones." Careful, selective application of certain fatty acid insecticidal oils, insecticidal soaps and pyrethrins can control early emergence of harmful insects without overkill.

The website offers a basic insecticidal soap recipe and variations. You'll need pure soap -- no dish soap or degreasers -- distilled water, and a spray bottle for the basic recipe. After that, such additives as cayenne pepper and garlic may be helpful. This site and others offer easy, inexpensive recipes for routine, eco-friendly insect controls.

And finally, the best defense in the garden is a good offense. Keep your plants healthy, says Knepler. Adequate sun and enough water (an inch and a half of rainfall or supplemental watering per week) will allow your plants to thrive, attract beneficial insects and create a sustainable and beautiful garden for years to come.

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