Why You Shouldn't Buy Ladybugs for Natural Pest Control in your Garden
In the post on 10 Online Gardening Communities You Should Join I recommended Twitter because rarely a day doesn’t go by that I don’t learn something new.
Recently, I was observing a @GroundChat discussion when @BugLadySuzanne mentioned that ladybugs that you can purchase for your garden are trapped in the wild, and that these ladybugs can carry parasites and diseases that will infect ladybugs native to your area.
I sent her a few questions about the practice because I always assumed ladybugs were raised in a more sustainable manner, and buying them to release in the garden was a good thing.
Below is the transcript of my Q&A with Suzanne on ladybugs, how they're harvested, and their role in garden pest control.
TreeHugger: How common is it that trapped ladybugs available for sale to gardeners?
Suzanne Wainwright: Almost all ladybird beetles sold in the US are wild harvested.
TreeHugger: How much of the retail market does this consist of?
Suzanne Wainwright: For homeowner 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 use more by commercial growers because they specialize on feeding on specific pests.
TreeHugger: Are there ladybug "farms" gardeners can order from if they don’t want to support the trapping of ladybugs in the wild?
Suzanne Wainwright: Companies like BioBest and Insect Lore have them for sale but often homeowners find them too expensive. An insect that works better as a general predator in the garden are green lacewings. These can be purchased from Beneficial Insectary for homeowner use.
TreeHugger: If you do buy ladybugs, how can one keep them from flying into a neighbor's yard once released?
Suzanne Wainwright: You typically can not 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 ladybeetles through their hibernation until they are ready to feed again but even then, this does not mean they will stick around.
TreeHugger: How serious of an issue are the parasites and diseases these wild-caught ladybugs carry? Do they affect other beneficial insects?
Suzanne Wainwright: 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 reducing the number of eggs laid by female ladybird.
TreeHugger: What can gardeners do to naturally attract ladybugs?
Suzanne Wainwright: 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.
TreeHugger: I once saw a ladybug "house" in a garden that didn't have any ladybugs at home. Are these a waste of time?
Suzanne Wainwright: Yes, waste of time.
TreeHugger: Is there something else homeowners can buy or make that would make a good "home" or nesting environment for ladybugs?
Suzanne Wainwright: Being that ladybird beetles have different overwintering sites I would think you would have to look at the region and then species
Also ladybirds don’t “nest." In colder climates they hibernate. How and where they hibernate depends on species. For example, many northerners know that Harmonia axyridis (Asian ladybird) likes to over winter in people houses where Coleomegilla maculata (spotted ladybird) likes to be in the leaf litter outside. Now you can get PredaLure which the USDA has shown to attract ladybirds.
I want to thanks 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. A few years ago when I stopped using chemicals in my garden I saw an increase in pests and beneficial insects like ladybugs. Whenever the aphid population increases I like to trap the ladybugs in my garden and place them on the affected plants.
In this video I recorded a few years ago in my garden I placed a ladybug on a poppy seed pod that was 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 out the beneficial bugs and start a bug fight instead of reaching for pesticides.