If you’ve got an infestation of aphids, thrips, mealybugs or whiteflies and you’re not squeamish about small-scale biological warfare, beneficial insects, also known as natural enemies, may be an attractive option.

Predators and parasitoids of many common garden pests can consume many times their weight in damaging pests, cleaning up your plants.

If you lived on the mainland, you could purchase a quart of ladybugs, a bottle of lacewing larvae or a jar of predatory mites. But in Hawaii we’re so vulnerable to new pests and diseases that can hitchhike with insects that our quarantine regulations prohibit bringing these animals into our state.

Don’t be discouraged. Many species of beneficial insects are already here and just need to be called to the dinner table. How does the backyard gardener do that?

First, learn who the good guys are. Scout around your garden once or twice a week to see who’s living there now. You might observe predatory insects scuttling quickly after their prey. Beneficial insect identification flashcards for Hawaii can be purchased for $10 from your local master gardener office or can be downloaded for free at go.hawaii.edu/BR.

Be sure to notice what these insect allies look like throughout their life cycle. Like butterflies, they might go through extreme metamorphosis. For example, young ladybeetles (ladybugs) resemble tiny alligators with pinchers, and like most teenagers they have a voracious appetite — for aphids, whiteflies and mealybugs. See if you can spot "aphid mummies" and other signs that pests have been parasitized.

Second, make beneficial insects feel welcome. These insect allies need food (pollen and nectar), water and habitat. Your backyard or garden should offer all of these elements year-round for beneficial insects to call it their home.

Lure ladybeetles, hoverflies and parasitic wasps by growing rows of buckwheat and cilantro and letting them flower. Minute pirate bugs will enjoy marigold and cosmos.

Trichogramma wasps relish sunn hemp and cowpea. Use an organic mulch on the soil surface to appeal to predatory spiders. Install a nesting block for key-hole wasps and aphid collecting wasps.

Third, control ants in the garden. Certain ants actually raise and protect herds of aphids, mealybugs and whiteflies on garden plants, feeding off their sweet secretions called honeydew.

Treat trees by wrapping sticky barriers around the trunk (such as Tanglefoot insect barrier), remembering to check and replace them regularly. Boric acid bait stations placed near ant nests and on trails can also help.

Finally, put away most of your pesticides. The home garden is a great place to use products with low toxicity to people and animals, products that biodegrade quickly. Horticultural oils, insecticidal soaps, microbial and botanical insecticides meet this need. Look for them in your garden store.

Avoid using broad-spectrum insecticides such as organophosphates (such as Malathion), carbamates (such as Sevin) and pyrethroids (such as Talstar). Major outbreaks of aphids and scales in the garden are often the result of having used broad-spectrum pesticides, which kill natural enemies.

Jody Smith is an Oahu master gardener and can be reached at OahuMg@ctahr.hawaii.edu.