If you have a vegetable or flower garden, you've likely heard the phrase beneficial insects. But, what are these insects, and why and how are they beneficial? Most folks think about bees and butterflies, but the realm of beneficial insects is far greater than that. In fact, there are several dozen insects with advantages to offer. Your garden will be infinitely healthier, more productive, and greener when you create spaces that welcome these helpful insects.
Why Are Beneficial Insects Important?
Our gardens are naturally home to thousands of bugs. Most of them are harmless, a few are incredibly destructive, and a good percentage are helpful. These helpful insects provide several essential functions in the garden. Without them, gardening would be so much more work!
There are two main types of beneficial insect:
Pollinators: All plants need pollination, and bugs and insects do this for free every day. Believe me, if you had to do this yourself, none of your gardens would be pollinated. It's a lot of work! Helpful insect pollinators include butterflies, bees, moths, and flies.
Predators: Many insects eat the pesty bugs and are quite happy to do so. For example, ladybugs love a meal of aphids. Aphids are a common and prolific garden pest, so the more ladybugs in the garden, the better. Other useful predatory insects include praying mantises, green lacewings, and pirate bugs.
Another type of predatory insect is the parasitizer. These insects attack pests a little differently. In most cases, the parasite insect lays its eggs on or in the bug. After the eggs hatch, the larvae eat the host bug. Wasps are most well known for this.
How Do Beneficial Insects Help The Garden?
- Natural Pest Control
- Flower and Vegetable Pollination
- Reduces Need for Pesticides and other Chemicals
- Saves Money (you won't have to buy pesticides)
- Reduced Resistance – Many insects are demonstrating increased resistance to pesticides. The more we use them, the greater the chances of pests developing resistance.
- Long-Term Solution – When you have good populations of beneficial insects, your garden will be healthy for years to come.
The Importance Of Not Using Chemical Pesticides
“When we kill off the natural enemies of a pest, we inherit their work.”– C.B Huffaker
Pesticides don't differentiate between good, bad, or harmless insects. The majority of pesticides kill every bug they come in contact with, which can be seriously detrimental to the overall health of your garden. Remember all the natural benefits these insects provide, totally free of charge. We know how frustrating it is to have an infestation of squash bugs or aphids, but there are better ways to combat them than to spray pesticides.
When you use chemicals to fix the problem, you are actually creating more problems for yourself and your garden. There will be fewer pollinators, which means many flowers may not bloom. Without predatory insects to naturally control pests, you may experience even larger influxes and infestations of bugs that harm your crops. And, that will mean you need to apply more pesticides, leading to a never-ending cycle of dependence on the chemicals to maintain the basic health of your garden. On top of that, insects have quick life-cycles and adapt way faster to new conditions than humans. Bugs become immune to pesticides, requiring larger and larger applications until it becomes quite expensive and more dangerous.
We, as a population, have been sold on the idea of quick and easy garden fixes, and in many cases, are reliant on them. It's time to step back, look at the whole picture, and think about the future of our gardens. Pesticides leech into the ground, drift through the air, and end up in our freshwater supplies. Soil, air, and water are necessities to life, and when they get poisoned, it is extremely difficult to reverse. It doesn't end there, though. Many wild animals are harmed by ingesting poisoned insects and rodents.
Sometimes the use of pesticides is necessary, but it should always be the last resort. When you focus on building a healthy garden foundation instead of fixing a problem quickly, you, your garden, and the earth benefit.
Be proactive, and be patient, and the rewards will be rich! Don't wait for the pest to arrive, and then combat it. Create a garden that is already prepared to deal with the harmful insect, and watch them disappear naturally.
The Basics Of Attracting Beneficial Insects
Like all creatures on earth, beneficial insects need access to food, water, and a safe place to call home. A greater diversity of plants will draw in a more extensive assortment of beneficial insects. Some beneficial insects arrive in the garden before there are pests to snack on and must supplement with pollen and nectar. If these aren't available, they won't stick around for when you need them most.
- Plant early blooming flowers and herbs. Flowers with small, flat blossoms are best. Most beneficial insects can't access the nectar in tubular or deep flower heads. Alyssum, carrots, and parsley, leftover from the previous year's garden, are especially valuable.
- Grow late-blooming flowers, as well, so the insects have enough food after other sources are exhausted. Lavender, mint, lemon balm, fennel, dill, sage, Queen Anne's lace, yarrow, and goldenrod are all excellent. When there is a broad mix of options throughout the entire season, beneficial insects are more likely to stick around for many years. Beneficial insects will leave your garden if they can't find sufficient food late in the season. Late-blooming flowers are also vital for fall-migrating species.
- Plant a wide variety of flowers, herbs, vegetables, and shrubs. The more diverse the landscape is, the more beneficial insects will find it a suitable home. Every beneficial insect has its nectar and pollen preferences. Variety is the spice of life!
- Provide several shallow sources of water throughout the garden so the beneficial insects can hydrate.
- Provide little hiding places around the garden to give beneficial insects a safe place to live and shelter. Hollow branches, small bunches of twigs, hedges, and shrubs are all excellent habits for insects.
- Research which beneficial insects, and which pests, are common in your area. Plant specifically for those species to be the most effective.
- Don't use pesticides! Pests often become worse after using pesticides because all the beneficial bugs that were combating them are now gone.
- Grow native plants to attract native insects. This is essential for the health of your garden and the earth. Our native plant populations are declining, and along with them, many native beneficial insects that rely on those special plants.
19 Beneficial Insects And How To Attract Them
The key to employing beneficial insects is to learn who is who in the garden. After all, there are a lot of bugs out there. When you see an insect or bug, do some investigation. Don't assume every insect you see is terrible or there to cause harm. Take some time to learn the coloring and characteristics of the good ones, and when you see them, tell them thanks and good job! A great way to say thanks to these beneficial insects is to provide a safe space where they can do what they naturally do best.
Aphid Parasite Wasp
This minuscule wasp is a mighty aphid-fighter. It hones in on plants infested with aphids, then injects an egg into the pest. Once the egg hatches, the larvae eat the aphid from the inside out. Other aphids in the area emit an “alarm” pheromone to the intruder, which sends the whole aphid colony fleeing. Sometimes, they all fall to the ground and die. Gross, that's for sure, but quite effective at combating this common garden pest! One aphid parasite wasp will lay eggs in up to 300 aphids.
How To Attract: Adult wasps enjoy pollen and nectar, especially from umbrella-shaped flowers. Yarrow, Queen Anne's lace, fennel, dill, and zinnias are irresistible.
An odd-looking insect, which looks like a cross between a praying mantis and a squash bug, the Assassin Bug is an excellent garden friend. These bugs eat aphids, beetles, caterpillars, and leafhoppers, along with other bugs. Assassin bugs aren't picky and will eat any insect that crosses their path, including beneficial ones. One caveat, these bugs deliver a painful bite (not deadly – it just hurts!), so steer clear of them if you see them. If your garden space is teeming with pests eating your plants, Assassin Bugs are wonderful to have around.
How To Attract: Assassin Bugs are attracted to Queen Anne's lace and daisies. Plus, they like a wide range of insects to eat.
Honey bees are the most commonly known bee pollinator, but they aren't actually the best bee for the job. The honeybee isn't native to North America, and while they do a good job, native bumblebees, carpenter bees, mason bees, miner bees, and leaf-cutter bees are much better because they are specialized. Native bees vary by region, so it is important to learn the ones specific to your locale. There are 49 bumblebee types native to North America and over 2000 other bee species. All of them work non-stop as pollinators. It is estimated that native bees pollinate 80% of all flowering plants. There is no one way to attract wild bees – their preferences vary as widely as their sizes, shapes, and colors. Besides planting specific flowers to attract bees, it is essential to make sure there is water and shelter for them, too.
How To Attract: Check out these guides to see which bees are native to your area. Then, plant flowers to attract specific species. Wild bees prefer wildflowers and native plants, so be sure to grow a wide variety of them.
Native Bees, Search For Plants By Region (in the top right corner, you can narrow the choice by choosing a state, type of plant, and so forth.)
These minuscule bugs eat thrips, whiteflies, mites, caterpillars, Mexican bean beetles, and leafhoppers. While they are mostly beneficial, they do have a bad habit of munching on garden plants if they can't find any other food. Only work to attract these if you already have a big pest problem.
How To Attract: Goldenrod, soybeans, and pigweed are the favorite plants for Big-Eyed Bugs. Big-Eyed Bugs are omnivores and will eat insects, plants, and nectar.
By far one of the prettiest beneficial insects, butterflies are excellent pollinators. Plus, they are lovely to watch as they flit around the garden!
How To Attract: Butterflies prefer large, brilliantly colored flowers. They are also attracted to scent. To ensure butterfly populations, plant a diverse array of big, beautiful flowers. Also, butterfly caterpillars are host-specific, meaning they will only eat the leaves of one plant. If you want to attract a specific butterfly, you must plant the specific flower the species needs. Milkweed, lupines, asters, violets, sedum, clover, and black-eyed Susan are just a few of the flowers butterflies seek out.
This beneficial bug eats leafhoppers, aphids, thrips, mites, cabbage worms, and small caterpillars. The nymph damsel bug is voracious and will eat many insects bigger than itself. Damsel bugs lay their eggs in low-growing grassy areas.
How To Attract: Damsel bugs like tall grasses to hide in, as well as fennel, mint, goldenrod, and caraway plants.
The young larvae of this insect have enormous appetites for mites, aphids, caterpillars, and problematic bugs. In a week, larvae can eat up to 200 aphids! They easily earn their nicknames, "aphid lion" and "aphid wolf." Adult Green Lacewings feed on pollen and nectar, so to attract them to the garden means planting the flowers they love.
How To Attract: Cosmos, yarrow, goldenrod, coreopsis, Marguerite daisies, and Queen Anne's lace attract adult Green Lacewings.
Both adult ground beetles and their larvae eat pests, including the Colorado potato beetle, asparagus beetles, cutworms, corn earworms, cabbage root maggots, slugs, and caterpillars. One larva can eat up to 50 caterpillars. These insect eaters aren't attracted by specific plants; they like a diversity of perennials to make their homes. They also look for hiding places, like under rocks and boards. If you have a slug issue, ground beetles are great to have around because they congregate in the same areas that slugs do. – damp, dark places.
How To Attract: Provide a diverse habitat, including perennial shrubs, rocks, and boards for them to call home.
Hoverfly larvae eat aphids, thrips, caterpillars, and mealybugs. The adults eat pollen and nectar and are incredible pollinators. Hoverflies resemble tiny yellowjacket wasps but don't let that worry you. They are one of the best beneficial insects for the garden, and they don't even have a stinger.
How To Attract: Hoverflies appreciate a diverse mix of flowers and herbs. Daisies, marigolds, lavender, asters, dill, fennel, and feverfew are just a few effective choices.
Not just good luck to you, a population of ladybugs is fortunate for a garden, as well. Both adults and larvae eat copious amounts of aphids, mites, soft-bodied insects, and bug eggs. Larvae are known to consume up to 40 aphids an hour! The adults also enjoy a feast of nectar and pollen. Ladybug larvae are bright yellow little eggs, which they lay on plant stems and leaves.
How To Attract: Adult ladybugs are attracted to coriander (cilantro), dill, fennel, alyssum, thyme, oregano, yarrow, and coreopsis.
Leaf Miner Parasites
If you've seen the telltale sign of a leaf-miner bug infestation, you know how frustrating it can be. Leaf miner larvae tunnel through leaves as they eat, leaving brown squiggles behind. They are rarely selective and will destroy crops of leafy greens, tomato plants, and even citrus trees. If left unchecked, they cause extensive damage and pave the way for bacterial or fungal diseases to infect your plants. The Leaf Miner parasite is a tiny, non-stinging wasp that uses the Leaf miner bug as a host for its eggs and larvae. The wasp kills the bug, lays its eggs inside, and when the larvae hatch, the bug is their food. An adult Leaf Miner parasitic wasp lays upwards of 300 eggs in its short month-long life-cycle. The adult wasps eat nectar and pollen.
How To Attract: Adult Leaf Miner parasites prefer dill, parsley, yarrow, zinnia, cosmos, sunflowers, marigolds, alfalfa, and clover.
As the name suggests, this beetle eats all the mealybugs. However, the Mealybug Destroyer also enjoys feasting on aphids and other soft-scaled bugs. Adults and larvae alike eat the garden pests. Female Mealybug Destroyers have developed some sneaky tactics; they lay their eggs in or nearby a mealybugs cotton-like egg casing – at a rate of 10 eggs a day for 50 days! Once the Destroyer larvae hatch, they feast on the eggs off the mealybug.
How To Attract: Dill, fennel, goldenrod, and sunflowers attract Mealybug Destroyer adults. However, most Mealybug Destroyers cannot deal with cold weather and don't naturally occur in particularly cold climates. To keep a stable population of them, they'll need to be purchased each spring. Warmer zones will be able to host them without an issue.
This predatory insect feasts on spider mites, aphids, caterpillars, and thrips. Pirate Bugs are aptly named, as they have quite the gruesome method for eating their prey. These bugs pierce their victims with long sharp beaks and suck the juices out. Pirate Bugs are especially useful at crippling spider mite populations, eating upwards of 30 per day. While both larvae and adult pirate bugs primarily eat other insects, they also feed on pollen and plant juices.
How To Attract: Pirate Bugs prefer laying their eggs on corn, tomatoes, soybeans, and grain crops. Sweet clover, daisies, alfalfa, vetch, caraway, fennel, and mint attract Pirate Bugs.
One of the most well-known beneficial insects, Praying Mantis' eat a wide variety of insects. Moths, beetles, flies, and grasshoppers are all fair game. The Praying Mantis is not selective and will also eat other beneficial insects, like bees, butterflies, and even hummingbirds. If you have a lot of pests to deal with, the Praying Mantis is what you need. They may be problematic, though, if food sources are low and they start eating all the other beneficials.
How To Attract: Praying Mantis' like the protection of tall grass. They are also drawn to marigolds, dill, and shrubs.
These flies look like horseflies, but they don't attack people, thank goodness! Instead, Robber Flies spend their days attacking bugs of all sorts, including beetles, wasps, leafhoppers, grasshoppers, and mosquitoes. Unfortunately, Robber Flies don't discriminate on who they eat and will also kill beneficial insects. Their usefulness greatly outweighs any side effects, though, so it is good to have them around the garden.
How To Attract: Robber Flies like to choose from various bug snacks, and as long as there is food, they'll stick around. A diverse array of plants will host an extensive buffet for the flies.
A predator to Colorado potato beetles, Mexican bean beetles, caterpillars, cucumber beetles, cabbage loopers, cabbage worms, flea beetles, corn rootworms, beet armyworms, and aphids, the Soldier Beetle is important to have in the garden. Both the larvae and adult Soldier Beetles eat voraciously, preying on almost 100 different pests.
How To Attract: Soldier Beetles like flowers with compound blossoms, like zinnias, goldenrod, hydrangeas, milkweed, and marigolds. The female adults will drink the nectar and lay their eggs on the foliage of these plants.
While not technically an insect, spiders are great garden friends. They don't just eat flies; they also eat mosquitoes, wasps, aphids, grasshoppers, and fruit flies. Spiders have no interest in plants, so you never have to worry about them harming your vegetables or herbs.
How To Attract: Spiders need adequate space to spin their webs. If you see spider webs, don't tear them down unless absolutely necessary.
This large family of parasitic flies includes over 1300 species in North America. Most species resemble houseflies in some way but are much smaller. Tachinid flies feed on beetle larvae, caterpillars, grasshoppers, and other bugs. Many Tachinid flies display an unusual trait for insects; the eggs mature within the mother, and when she lays them, they hatch immediately. Among the many tachinid flies, some types specialize. For example, one tachinid parasitizes corn borer larvae, while another only attacks the cabbage looper caterpillar.
How To Attract: Adult Tachinid Flies are attracted to dill, cilantro, sweet clover, carrots, Queen Anne's lace, and buckwheat.
Wasps – Brachnoid & Trichogramma
The idea of encouraging wasps may seem like a dangerous idea, but not all wasps sting. Neither the Bracnhoid nor Trichogramma wasps are dangerous to humans; they do not sting.
Brachnoid – Wasps of this species lay their eggs on the back of caterpillars, including the tomato hornworm. The eggs appear as a white cocoon on the caterpillar's back. Once the eggs hatch, the larvae eat the caterpillar – alive!
Tomato hornworms are a considerable problem for tomato plants because they eat all the foliage and kill the plant. However, a little-known fact is that these troublesome hornworms morph into Sphinx Moths. And Sphinx Moths are excellent pollinators and actually benefit the garden. If you have a problem with the hornworm, try increasing the population of brachnoid wasps to deal with the issue naturally. But, please don't kill all the hornworms you see; instead, try relocating them to a safe area far from the garden with plenty of green foliage for them to eat.
Trichogramma – These wasps lay their eggs inside the body of several pesty insects, where, once hatched, the larvae eat the host. Trichogramma wasps parasitize Mexican bean beetles, Japanese beetles, squash bugs, green stinkbugs, corn borers, grasshoppers, and Gypsy moth caterpillars.
How To Attract: Adult wasps of both types feed on nectar and pollen. Plant chamomile, dill, fennel, yarrow, allium, and alyssum to attract them.
Best Plants To Grow For Beneficial Insects
You might have noticed that several plants are mentioned repeatedly as plants beneficial insects prefer. There are certainly some rock-star plants that should be planted in every garden as general pest control. Even just a few of these plants will significantly improve your garden's health and well-being.
Due to its high-quality pollen and nectar, dill is popular with many beneficial insects. From butterflies to bees to leaf miner parasites, dill never wanes in popularity. One of the reasons is that it flowers early, providing a wealth of nutrition when many other plants are still maturing. And, the flowers are prolific and small, perfect for all the little insects. Dill is the favorite home of Black Swallowtail caterpillars. Be sure to plant enough dill for yourself, as well. Dill pickles are a must!
The bright, sunny flowers of the marigold are a favorite habitat for many beneficial insects. The flowers are also an excellent source of nectar. Not all marigolds are created equal, though. There are so many marigold cultivars; it can be challenging to get the best ones. The marigolds must be scented; avoid unscented varieties since they won't be any good in the garden.
Many new cultivars feature tight, frilly blooms; these are not easy for pollinator insects to access. Choose varieties with wide, open blooms or tiny clusters of many flowers. Plant the marigolds in a patch, as opposed to scattering them around the garden. Beneficial insects will be more attracted to a large mass of marigolds.
Queen Anne's Lace
Queen Anne's lace's appeal is geared towards pollinators with short nectar-gathering appendages, like bees, beetles, wasps, flies, some butterflies, and ants. This flower puts its nectar at the base of the plant, where it is easily accessible. Also, because Queen Anne's lace grows quite large, often reaching 6-7', it is a valuable habitat and host for many insects. Queen Anne's lace is a beautiful plant with huge flower heads that look like giant snowflakes.
Pollen sticks to the plant, creating an easy buffet for a host of bugs. Bees, butterflies, moths, wasps, beetles, and flies all enjoy goldenrods. The abundant little flowers are also extremely attractive to beneficial insects for food. Goldenrods' tall foliage also provides essential habitat for many bugs. These tall, striking golden-yellow flowers bloom from late August into September, making them a vital resource for all insects after most other food sources have died off. This is especially critical for fall migrating insects, like Monarch butterflies.
Insect pests are also attracted to goldenrod, and many beneficial insects hang out around the plant, happily eating the pests all day long.
A perennial flower with large lacy foliage and red, yellow, or white blossoms, Yarrow is attractive to many bugs. Yarrow grows up to 3' tall and has a mild, pleasant smell. Ladybugs, hoverflies, damsel bugs, green lacewings, predatory wasps, and pirate bugs all appreciate Yarrow nectar. For beneficial predatory insects, yarrow provides a wealth of food by attracting cucumber beetles, aphids, and flea beetles. When those pests go to the yarrow, the beneficial bugs will welcome them with an open mouth.
The honey-scented flowers are irresistible to many insect species, including hoverflies, bees, butterflies, wasps, and flies. The tiny, dainty flowers are the perfect nectar source for these beneficial insects. Aphids also really like Alyssum, and hoverflies enjoy eating aphids, making this a win-win. Not only are aphids flocking to the Alyssum instead of your vegetables, but they're also being taken care of by the hoverflies.
Now, it's time to start planning the garden and plan how to keep it healthy and free from pests, the natural way. Encouraging and maintaining spaces for beneficial insects to habitat and eat is essential for a flourishing garden. Don't forget to look into which native insects live near you and how to provide for them. Happy Gardening!