Beneficial Garden Insects: Identification Guide & How to Attract Them

Short list of great beneficial insects with pictures and tips for attracting these good bugs to your garden.

The average backyard hosts thousands of insects. Only ~10% are destructive. Most are beneficial or harmless. Beneficials fall into three categories:

• Pollinators: Essential for fruit/vegetable pollination.
• Predators: Eat pests.
• Parasitizers: Lay eggs on/in bad bugs; larvae feed on hosts, killing them.

You've likely seen these garden allies without formal introductions. Meet a few:

Ladybug larvae eat up to 40 aphids/hour!

Green lacewing adults eat pollen/nectar; larvae (little alligators) suck juices from soft-bodied insects including caterpillars.

Praying mantis decimates grasshoppers but too many eat other beneficials, butterflies, bees, each other!

Wolf spiders—often overlooked but effective pest controllers. Attracted by movement, eat many live insects.

Ground beetles (adults and larvae) eat nematodes, caterpillars, thrips, weevils, slugs, silverfish.

Soldier beetles prey on Mexican bean beetles and Colorado potato beetles. Attracted to compound blossoms. Spined soldier beetle resembles stink bug—don't mistake it!

Hoverflies mimic yellowjackets but don't sting. Pollinators; larvae voraciously suck juices from aphids, caterpillars, beetles, thrips.

Parasitic wasps—tiny, unseen but effective:

• Braconid wasps lay eggs on tomato hornworms (white cocoons on worm's back). Leave parasitized worms—larvae eat from inside out, hatch into more wasps.
• Trichogramma wasps lay eggs in 200+ pest insect eggs, preventing hatching.
• Tachinid flies (small housefly lookalikes) parasitize corn borers, gypsy moth caterpillars, grasshoppers, Japanese beetles, Mexican bean beetles, squash bugs, green stinkbugs.

Attracting Beneficial Insects

Like all creatures, beneficials need water, food, shelter. Provide these for an inviting garden.

Diverse plants attract diverse insects. Many beneficials appear before pests—need alternative food (pollen/nectar) to stay.

• Early bloomers with tiny blossoms (alyssum) or biennials left to bloom (carrots, parsley) draw beneficials in spring.
• Later: Compound blossoms (yarrow, goldenrod, Queen Anne's lace) and flowering herbs (lavender, mint, sage, dill, fennel, lemon balm).

Warning: Chemical pesticides kill good and bad bugs alike. Even "natural" pesticides (pyrethrum, rotenone) kill many beneficials.

As Eleanor Perenyi writes in Green Thoughts: "Every insect has a mortal enemy. Cultivate that enemy and he will do your work for you."

~ By Robin Sweetser