Why You Shouldn't Buy Ladybugs for Natural Pest Control in Your Garden

Got pests? Encourage native ladybugs to inhabit your garden instead of buying wild-harvested ladybugs to manage unwanted insects. Purchased ladybugs are expensive and potentially disease-carrying, threatening native bug species already living in your garden and the surrounding area. Your best bet is to attract and encourage native ladybugs to thrive and flourish, which will responsibly deter unwanted pests.

In an article called "10 Online Gardening Communities You Should Join," I recommended getting on Twitter (now X) because rarely a day goes by that I don’t learn something new. Case in point: I was following a discussion in which Suzanne Wainwright (also known as @BugLadySuzanne) mentioned that ladybugs (aka lady beetles and ladybirds) purchased for your garden are usually trapped in the wild and can carry parasites and diseases that will infect ladybugs native to your area.

Since she's an entomologist with more than 20 years of experience and specializes in biological pest control, I wanted to ask her more about this practice because I always assumed ladybugs were raised more sustainably. Isn't buying them to release in a garden a good thing? Here's what I learned.

Treehugger: How common is it that trapped ladybugs are available for sale to gardeners?

Suzanne Wainwright: Almost all ladybird beetles sold in the United States are wild-harvested.

How much of the retail market does this consist of?

For homeowners buying the convergent ladybird (Hippodamia convergens) and the Asian lady beetle (Harmonia axyridis), those are all wild-harvested.

The only commercially produced (reared at a commercial insectary) "red" ladybirds are the two-spot ladybird (Adalia bipunctata) and the spotted ladybird (Coleomegilla maculata).

There are a few other specialist ladybirds like Delphastus pusillus, Stethorus punctillum, and Cryptolaemus montrouzieri, but homeowners do not typically buy them. They are used more by commercial growers because they specialize in feeding on specific pests.

Are there ladybug "farms" gardeners can order from if they don’t want to support the trapping of ladybugs in the wild?

Companies like Insect Lore have them for sale, but often homeowners find them too expensive. [For example, 1,000 ladybugs cost around $15 and are enough to cover a home greenhouse.] An insect that works better as a general predator in the garden is the green lacewing. These can be purchased from Beneficial Insectary for homeowner use.

If someone buys ladybugs, how can they keep them from flying into a neighbor's yard once released?

You typically cannot keep the ladybirds around unless you cage them on the plant. Even then, there is no guarantee they will feed on the pest insects because they are harvested while hibernating. Sometimes harvesters will hold the lady beetles through their hibernation until they are ready to feed again, but even then, this does not mean they will stick around.

How serious of an issue are the parasites and diseases these wild-caught ladybugs carry? Do they affect other beneficial insects?

If the parasites are not in the area, you could be introducing them. I have seen this happen in greenhouse settings. The parasites only attack ladybird beetles. Research has shown that 3–15% of harvest ladybird beetles carry the internal parasite Dinocampus coccinellae. This same study found many of the harvested beetles to be infected with Microsporidia, a disease that shortens the ladybird’s life span and reduces the number of eggs laid by the female ladybird.

What can gardeners do to attract ladybugs naturally?

Many ladybird beetles feed on pollen as part of their diet as adults. Provide heavy pollen-producing plants like sunflowers and other composite flowers. Also, do not spray pesticides. Even approved for use in organics, pesticides can have impacts on ladybird beetles.

It’s important to learn to identify all life stages of the ladybird beetle. Most only know adults and may not recognize the immatures which do a lot of the feeding on other insects and mites.

I once saw a ladybug "house" in a garden that didn't have any ladybugs at home. Are these a waste of time?

Yes, waste of time.

Is there something else homeowners can buy or make to make a good "home" or nesting environment for ladybugs?

Since ladybird beetles have different overwintering sites I would think you would have to look at the region and then the species.

Also, ladybirds don’t "nest." In colder climates they hibernate. How and where they hibernate depends on the species. For example, many northerners know that Harmonia axyridis (Asian ladybird) likes to overwinter in people's houses, where Coleomegilla maculata (spotted ladybird) likes to be in the leaf litter outside.

You can also get PredaLure, a pheromone that the USDA has shown attracts ladybirds.

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I want to thank Suzanne for taking the time to answer these questions. I’m glad to learn that those little houses don't do anything to increase the ladybug population in the garden, because I was planning on installing one.

Another point to consider is how the wild-harvesting of ladybugs impacts those bugs' home habitats. In North America, many are taken from California. Garden Myths writes, "The popularity of purchased lady beetles has skyrocketed and nobody knows what this is doing to local populations. Imagine someone coming into your neighborhood to collect native bees, for shipment across the country." People would be understandably outraged.

Furthermore, convergent ladybugs (named for the converging white marks on their thorax)—the most commonly sold variety—are highly competitive and could cause harm to less aggressive native species wherever they end up.

Adding to the problem, ladybugs don't stay put. Introducing 1,000 ladybugs to a backyard may work for a time, but as soon as their food source is gone (aphids), they'll fly elsewhere to look for more. A single adult ladybug will eat 50 aphids a day, so there's no point in using them for anything less than a full-blown infestation.

Research has shown that you need large amounts of ladybugs for effective control. "One large, heavily infested rose bush in the landscape required two applications of about 1,500 lady beetles each, spaced a week apart. Most packages sold in stores contain only enough lady beetles to treat one aphid-infested shrub or a few small plants."

According to a blog by the University of California Division of Agriculture and Natural Resources: "About 95% of released beetles in research studies flew away within 48 hours. The remainder were gone within 4 or 5 days. Lady beetles are unlikely to lay eggs on the plants they are released on. If aphids return a week or two later, gardeners will need to release more lady beetles, hose aphids off with water, use insecticidal soap sprays, or wait for other native aphid natural enemies to fly in."

A few years ago, when I stopped using chemicals in my garden, I saw an increase in both pests and beneficial insects like ladybugs. Whenever the aphid population increases, I trap the ladybugs in my garden and place them on the affected plants.

In this video I recorded in my garden, I placed a ladybug on a poppy seed pod being attacked by aphids. The ladybug made short work of the pests, and I was able to harvest poppy seeds. The next time you have a bug problem in your garden, seek to attract native ladybugs—a most beneficial bug— and start a bug fight instead of reaching for pesticides.