Beneficial Beetles

Boost Your Garden's Health with Beneficial Beetles

A few fun facts about beetles: Some of them (like lightning bugs) can glow in the dark to communicate. Beetles are eaten by humans more than any other insect. And… if you garden, beetles can make you look really, really good.

Few beneficial insects do more to help gardeners minimize pests, pollinate plants, and improve soil health.

And while not all beetles are good news for your garden (Japanese beetles and cucumber beetles, for example, aren’t particularly great to have around your plants), many of them make exceptional helpers.

We’re going to take a look at three of them: ladybugs, ground beetles, and soldier beetles.

Ladybugs

Ladybugs, also known as ladybird beetles, have been described as one of gardeners’ best friends. For one thing, the way ladybugs gorge themselves on aphids — sap-sucking garden pests that weaken and kill plants — is a thing of beauty. One ladybug can produce several thousand aphids in its lifetime (beginning as larvae, when they can consume up to 5-10 aphids an hour).

Ladybugs like munching on other harmful pests, too, including mites, scales, and mealybugs.

Attract them

To lure ladybugs to your garden, provide some of their favorite plants and flowers, including dill, fennel, yarrow, and marigolds. 

If you’d like to be a particularly gracious host, provide ladybugs a safe haven for the winter. Old stems are a great choice, or you can set up a hotel by creating a simple structure using natural materials like bamboo canes, straw, and small twigs bundled together and placed in a sheltered spot.

Ground beetles

Some may not find ground beetles quite as cute as ladybugs, but from a gardening point of view, ground beetles deserve just as much appreciation. 

Ground beetles excel at hunting and eating garden pests. They eat slugs, snails, cutworms, caterpillars, and other harmful insects that can damage plants. And like ladybugs, both adult ground beetles and their larvae are predatory, making them effective at controlling pests throughout their lifecycle. 

Ground beetles also play a role in improving soil health. While they’re mostly predatory, some species also scavenge for food, which in their case, includes decaying plant material and other organic debris in the soil. That process breaks down organic material, which contributes to soil fertility. 

Some ground beetles specifically eat dead organic material. By doing that, they help accelerate the decomposition process and recycle nutrients back into the soil.

And because ground beetles like to burrow into the ground, they help aerate soil, which in turn, allows water and nutrients to penetrate deeper, where plant roots can access them.

Attract them

To attract ground beetles, offer a variety of plants that provide both food and shelter. Here are a few suggestions:

Nectar and pollen sources:

Perennial flowers: Goldenrod, asters, coneflowers, yarrow

Herbs: Dill, parsley, cilantro, fennel

Ground cover and habitat:

Clover: White clover, Dutch clover

Grasses: Native bunchgrasses, fescues

Try to keep tilling and digging to a minimum so you don’t disrupt the ground beetles’ habitat.

Soldier beetles

Soldier beetles are highly beneficial to gardens, too, beginning with natural pest control. These beetles feed on aphids, caterpillars, and grasshopper eggs, along with two beetles that are harmful to gardens, Mexican bean beetles (which eat legume crops) and Colorado potato beetles (which kill plants in the Solanaceae family, including eggplants, peppers, potatoes, and tomatoes).

Both adult soldier beetles and their larvae are predatory.

Soldier bugs like to indulge in nectar and pollen, too, meaning they help with plant pollination.

Attract them

Soldier beetles like gardens with a variety of nectar-rich flowers including goldenrod, milkweed, and marigolds. And if you provide a natural habitat — tall grasses, flowering shrubs, and undisturbed areas, you’ll be even more likely to attract them.

General tips

We’ve covered some tips that will help you attract beneficial beetles, but we’d also like to mention a big don’t: applying chemical pesticides. That would only put the lives of beetles, and other beneficial insects, at risk.

Also, the beetles that visit your garden will appreciate a water source. To help them, put out a shallow dish with pebbles and water, where they can drink without risk of drowning.