Beneficial insects that prey on pests can be a gardener’s best friend, but many of the predatory insects sold in stores and online are not the right choice for effective biological control. To clear up misconceptions about beneficial insects and explain the best way to get more in your garden to manage insect pests naturally, my guest this week is Suzanne Wainwright-Evans of Buglady Consulting.
Suzanne is a horticultural entomologist who works with greenhouses, nurseries, theme parks and landscapes — anywhere that pest problems persist. At each site, she conceives a plan to conserve and promote existing beneficial, predatory insects that prey on pests, and she also implements what she calls “bug in a bag” solutions” — releasing shipped-in insects that were raised in federally regulated bug farms.
Suzanne is a graduate of the University of Florida with degrees in both entomology and environmental horticulture and resides in Pennsylvania. She’s been involved in the green industry for more than 30 years with a primary focus on biological control and using pesticides properly. In 2020, the Association of Natural Biocontrol Producers presented Suzanne with the ANBP Award of Excellence for her extraordinary contributions to the field of augmentation biological control and its use in integrated pest management, known as IPM.
The reason I picked this week’s topic and brought in Suzanne is because of this question that a listener wrote in: “I’m looking for information on native mantis and lady beetles. I’m always passing along info about the difference between native and non-native. Many people don’t know about this at all. Our gardening group is trying to be no-chemicals and turning to beneficial insects, but some are ordering these insects online and not getting the native. Can you do a show on this? I would love to breed our native mantis.”
This question is a great launching off point for a conversation with Suzanne, and we can take the topic in all sorts of directions.
Gardeners these days talk so much about beneficial insects: attracting them, planting out a diverse garden, etc. However, while there are some people who have success attracting beneficial insects, others don’t have luck right away. When we see insects for sale in the garden center or online, it seems like a quick fix, but the reality is more complicated than that, as Suzanne explains.
Before proceeding with my conversation with Suzanne, I want to take a second to remind you that my new book was released this month. It’s titled “The Vegetable Gardening Book: Your complete guide to growing an edible organic garden from seed to harvest” and can be found both online and at local bookstores. It’s chock full of insider tips and new-to-you information that will help you step up your gardening game and tackle challenges.
And on tap for 2023 is my new Online Gardening Academy™ premium course, Organic Vegetable Gardening. Sign up for the waitlist here.
The Problem with Praying Mantises for Pest Control
In the case of praying mantis — or praying mantid — a very recognizable predatory insect, there are native mantis species in the United States as well as invasive mantis species that compete with the natives. But when it comes to using insects for biological pest control, Suzanne doesn’t recommend mantises at all.
The insect that most of us envision when we hear “mantis” or “preying mantis” is the Chinese mantis because it is so large and visible, growing up to 5 inches long. Its egg case, called an ootheca, is also rather large — it’s just a little smaller than a golf ball — and very noticeable. The Chinese mantis is the species that is most often sold, ostensibly, for pest control.
“Even though the Chinese mantids are not native, they’ve been here so long, they’re part of the ecology,” Suzanne says.
The Carolina mantis, the state insect of South Carolina, is native to the United States and is also quite large. The males grow up to 2.5 inches long, and the females are just a little shorter.
Mantises, whether invasive or native, are voracious eaters, but they are also generalists. They could eat as many pollinating insects in your garden as they eat pests. “They’ll eat anything good, bad, indifferent,” Suzanne says. She explains that this has to do with how they capture prey: Mantises perch and then grab insects that fly past them or scurry by quickly. Insects that move quickly like that tend to be bees and butterflies — not slow-moving pests like aphids.
“If you just sit and watch mantids, they actually eat a fair amount of pollinators,” she says. “Yes, they are beneficial in the sense that they’re meat eaters, but for pests that often feed on plants, they don’t really target the pests we need to target that are often the true problems.”
Butterfly gardeners especially don’t want to have mantises around, according to Suzanne, because a mantis won’t make a distinction between a cabbage looper and a monarch butterfly.
“They don’t care because this idea of what is a pest and what is beneficial all depends on your perception, and a mantid’s perception just looks at everything and says that’s dinner,” she says.
Why Lacewings Are a Great Choice for Gardeners
Beneficial insects with a narrower diet are more effective for biological control because they target certain pests specifically.
“When I talk to anybody and say, ‘I work with beneficials,’ they’re like, ‘Oh, you work with ladybugs and praying mantids’ because that’s what we’re taught everywhere,” Suzanne says.
What she actually recommends for home gardeners are green lacewings, which are predatory in their larval stage and night-active pollinators as adults.
“They’ll lay their eggs on little stalks, and then when those eggs hatch, they climb on the plants and they eat a lot of different soft-bodied insects and mites,” she says.
Green lacewing larvae released in your garden will stick around because they can’t fly away during that stage of their life cycle. Lacewings are commercially reared on a large scale for pest management in agriculture. One of the problems with purchasing ladybugs is that they are often wild-caught, which means they are taken from their native habitats and could carry pathogens to where they are shipped. Lacewings grown in insectaries are pathogen-free.
“I was out in Washington State a few months ago in an organic apple orchard, and they’re actually using drones now to drop these lacewings onto the fruit trees as well as other parasitoids to control pests,” Suzanne shares. “We’re seeing this more and more — the drone releasing of beneficials on farm fields — and lacewings are a big part of that.”
A drone deploys beneficial insects over an orchard.
A drone can treat an acre per minute with beneficials, she says. In addition to lacewings, a popular beneficial insect for drone deployment is Trichogramma, a genus of wasps that kill moth eggs.
Homeowners can purchase lacewing larvae just like farmers can. GreenMethods, the retail website for Beneficial Insectary Inc. in Redding, California, is an online shop that Suzanne recommends. There, you can buy both lacewing larvae and eggs.
“There are not beneficials for every pest issue, but for a lot of the key plant-feeding pests — spider mites, western flower thrips, cotton/melon aphid, green peach aphid — we do have good biocontrol agents for,” she says. “But again, for the homeowner market, if they’re looking for something, a good generalist predator for your garden are the green lacewings.”
She recommends purchasing beneficial insects directly from insectaries, and not from companies that may have purchased them from another company that purchased them from another company that purchased them from an insectary. By the time those insects get to you, they may already be dead.
Insectaries tend to have websites that are poorly designed and antiquated, but that’s because the people behind those companies are too busy raising insects, Suzanne says. Flashy, attractive websites offering beneficial insects tend to belong to resellers.
Biodiversity & Beneficial Insects
Suzanne is an avid insect photographer so she plants for the benefit of bugs.
“Because I’m such an avid insect photographer, I want pest problems,” she says.
However, on her seven acres that she has been converting to meadow with native wildflowers, she has such biodiversity that it is hard for her to come by a pest problem. When the pests arrive, beneficial insects are soon to follow or are already waiting to prey on them.
“Even when I bring pests home, they’re gone in a day or two,” she says.
Suzanne has brought home plants heavily infested with thrips that are pest-free after two days of sitting on her patio. When she does notice a population of pests in her yard, she can’t wait a day to photograph them because they’ll be gone by then. There are just too many beneficials that pests can’t gain a foothold.
“Beneficials do not like monocultures,” Suzanne emphasizes. “They like biodiversity, and by having different plant heights and textural differences in plants, the beneficials do come in. People are so fixated on just having blooms, but it’s beyond just bloom.”
In studies, blooms have been removed from plants but the beneficials have been shown to arrive anyway because it’s not all about pollen, she says.
“Some beneficials do need pollen, but some don’t, and diversity is what’s more important,” she says. “But the traditional American landscape and garden is monocultures and rows and neat and tidy. And that’s just an invitation for pests to come in and create problems.”
For example, when Suzanne plants tomatoes, she also plants Alyssum because the flowers attract parasitoids that control aphid populations. The pollen in Alyssum is also very attractive to the minute pirate bug, a generalist predator that will feed on moths eggs, spider mites and thrips.
If you exclusively plant cultivars rather than natives, you may be raising flowers that bloom but don’t produce pollen. The pollen was bred out of them by commercial breeders — which makes the flowers empty refrigerators as far as pollen-eating insects are concerned.
“Just because you’re planting plants doesn’t mean you’re actually doing a service to the ecology,” Suzanne says.
It’s much better to plant natives that will in turn attract native insects.
“By having this mix and diversity, I’m inviting my local natives to come in to work for me,” Suzanne says.
She says that, having lived on the same property for 20 years now, she can walk outside, close her eyes and be able to tell what season it is just by the insect song she hears.
“I’ve learned through so many years how the songs change,” she says. “I couldn’t tell you what they are, but if you really go out and just spend some time listening, it’s amazing how different spring is from summer coming into late summer and fall and how the songs of the insects change.”
Identifying the Pests in Your Garden
When a plant is suffering from pest damage, it’s not always clear what kind of pest is the culprit, especially if it’s a night-active pest.
“Something I always recommend people to do is go out at night and walk through your garden with a flashlight because there is a whole different ecology going on at night,” Suzanne says.
Something many gardeners use to monitor and identify pests is a yellow sticky card. It will ensnare insects to let you know what kind of insects are visiting your plants and how severe infestations are.
To help gardeners identify insects using yellow sticky cards, Suzanne is working on her first insect poster. Rather than using images of living insects, she will use images of common pests stuck to yellow cards as well as beneficials that accidentally get stuck and neutral insects that aren’t a cause for concern.
The Challenges with Rearing Beneficials
In the United States, there is only one beneficial insect production facility.
That tells you that it’s really hard to rear insects, Suzanne says. The United States still imports 85% of its beneficial mites, nematodes and insects from other countries for use in agriculture here.
Information on raising beneficial insects is not readily available to home gardeners and even to professionals.
“The information at these insectaries is locked up so tight with proprietary information, and the university people don’t even really know how to mass rear insects,” Suzanne says. “It’s a science that is kept very close at hand so the competitors don’t figure things out.”
Nematodes — microscopic worms that kill grubs and other pests in soil — are an exception when it comes to learning how to raise them at home. However, even though the instructions for raising nematodes are available and it only takes two weeks, you won’t want to do it in your house because the smell is something else.
If you ever order nematodes for biological control and want to test the product for effectiveness, you can put some nematodes in a container with soil and then drop in a mealworm or wax moth larva from a pet store. (These are usually sold as reptile food.) The nematodes should go inside the larva and kill it within a few days, Suzanne says. The nematodes will also reproduce inside any larvae they feed on.
Nematodes that kill insects are known as entomopathogenic nematodes. They won’t kill or hurt mites, pets or people — only certain types of insects. If you are looking to control a specific pest with nematodes — they are sold in trays or in sponges — it’s important to make sure that the nematode species you plan to purchase actually preys on that pest species. Think of it like a lock and key system. The wrong key won’t unlock your pest issue.
Before Suzanne brings her houseplants in for the winter, she mixes nematodes with water and waters them into the plants’ soil so the nematodes will kill off fungus gnats within 7–10 days.
Fungus gnat larvae are so small that they won’t produce a noticeable smell when treated with nematodes, though even one of the large mealworms used in nematode rearing will have a wretched smell, and you will not want to breed nematodes on a grand scale after getting a whiff of that.
Outdoors, nematodes can be used to control Japanese beetles, iris borers, black vine weevils, fleas and many more pests.
Companies that raise nematodes have discovered and isolated the dispersal chemical that signals nematodes to exit a dead larva, and they isolated an aggregation chemical that attracts nematodes. A company called Pheronym has even worked with NASA to send nematodes into space to study how they behave in zero gravity — something that will be important to understand when attempting to grow food off-planet in the future.
Understanding Insect Communication to Make Better Pesticides and Controls
“We still know almost nothing about insects. It’s amazing,” Suzanne says. “The discoveries that are still happening, but the one thing we do know is — with the exception of mantids and dragonflies and things like that — most of our insects, they communicate through chemical cues because they really don’t see well.”
The compounds tell them when to reproduce, where to lay eggs, where to find food and when to flee from predators.
Researchers “are really starting to dial into these compounds and how we can use these to our advantage to manage pests other than just what we have been doing for 60 years of using really nasty neurotoxin pesticides to kill things,” Suzanne says. “Pest management, it is not your mother’s pest management anymore. We’re doing these big holistic approaches, really targeting chemistries.”
One new “designer pesticide” is so well targeted that it only kills a handful of spider mite species, she says. “It doesn’t even kill other kinds of mites. It doesn’t harm ladybugs. Where all our older chemistries just kill everything, and that’s what was used for decades and decades and decades. The new stuff is so targeted, and we’re using those in conjunction with our beneficial insects and mites.”
Good bugs are used in agriculture not just in organic growing operations but also in conjunction with synthetic pesticides as well as microbial pesticides, Suzanne points out.
Flying Insects You Should Love
Suzanne encourages gardeners to get to know all sorts of predatory and parasitoid flying insects.
Lady beetles (ladybugs) are widely known, but there are more species than even experienced gardeners realize.
Syrphid flies, also known as hover flies, are easily mistaken for bees or wasps but don’t sting. They prey on aphids and other pests.
Suzanne specifically plants flowers that who knows will attract tachinid flies, even though many people regard them as ugly and gross. Their larvae are parasitoids of caterpillars and beetle larvae. She has discovered that when she plants Pycnanthemums like narrow-leaf mountain mint, the plants become loaded with tachinid flies.
Conserving Beneficial Insects
“The farmers are realizing we have all these free workers that are showing up,” Suzanne says. “Let’s be targeted with our pesticides sprays and very narrow spectrum pesticides spray so that we can conserve our beneficials.”
Chemical pesticide manufacturers can now discern exactly how their products will affect beneficial insects at their different life stages — and they couldn’t do that just 20 years ago. With that knowledge now available, growers can determine when the most opportune time is to use a chemical pesticide while having the least impact on beneficials.
“A lot of things in life have gotten easier, but pest management has actually gotten a lot more complex because you have to understand all these systems and how they all fit together,” Suzanne says. “And that’s what my job is: to fit the puzzle pieces together.”
Gardeners have an advantage over Big Agriculture in that they don’t have expansive monocultures. Monoculture farms and greenhouses experience pest issues to an extent that gardeners will never see. Still, gardeners benefit from Big Ag’s lessons learned.
There is a shift in gardening toward educating consumers about the pitfalls of having giant lawns, lacking biodiversity and dumping out weed & feed each spring.
“The homeowners may not understand the whole complexity of what’s happening, but they’re kind of riding in the tailwinds of what ag is doing,” Suzanne says.
Homeowners have lost access to many broad-spectrum pesticides that were formerly on the market for everyday consumers, she points out.
“For the most part, a lot of the pests in your yard can be controlled with soaps and oils, and there are some really good soap and oil products that we use on big-scale ag, but then are repackaged under different brand names for the homeowner market,” she says.
The Important of Timing
If you know you have a recurring problem each spring with a certain pest, you can contact an insectary today and tell them where you live, Suzanne says. The insectary can tell you the best time to order insects so they will arrive at the right moment to release them in your garden.
You can also track growing degree days to forecast when pests will show up in your area. Growing degree days are about the accumulation of heat and will give you more accurate predictions of when bugs will arrive than a date you may find in a book or online.
It’s also important not to spray pesticides after releasing beneficial insects — you can kill your beneficials. Even oils applied before insect releases can repel beneficials.
I hope you enjoyed my conversation with Suzanne Wainwright-Evans on beneficial insects. If you haven’t listened yet, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
Do you endeavor to attract beneficial insects to your garden? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course membership opens in 2023. Sign up for the waitlist here.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out.
joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier.
joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
GreenMethods.com – Beneficial insects for home gardeners
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, AeroGarden, Milorganite, Soil3, Greenhouse Megastore, PittMoss, Territorial Seed Company, Earth’s Ally, National Wildlife Federation and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.