I'm not a big fan of pesticides, so when I found that my roses were being decimated by an aphid infestation last year, I decided to try using ladybugs for garden pest control. As a kid, my dad and I purchased live ladybugs from a home improvement store, only to have them all fly away as soon as we released them. While that childhood experiment with these beneficial insects wasn't particularly inspiring, I still knew that ladybugs love to eat aphids, so I thought there must be something I could do to keep them around.
After some research, I found some suggestions to help keep ladybugs in your garden after releasing them, though I read that most will still fly away. Once I found out where to buy ladybugs in my area, my son and I took the time to release them properly, and in a matter of days, my aphid problem was resolved.
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But I recently spoke with Molly Keck, a board certified entomologist specializing in integrated pest management for Texas A&M's AgriLife Extension Service. Keck explained that one of the disadvantages of buying ladybugs is that when people release ladybugs in their garden, they often take off. When I told her about my positive experience with live ladybugs, she suggested that my infestation was actually eradicated by local ladybugs that were already laying eggs on my plants at the same time I was out buying the insects at my local home improvement store.
So, was my experience just a matter of convenient timing? Did my approach to releasing the insects help them decide to stick around? And if buying ladybugs is pointless, what attracts them to your yard anyway?
What Are Ladybugs?
"Ladybugs are beetles," says Keck. "They are generally red with black spots, though they can be black with red spots, and there is one that is a gray color." Grouped in the Coccinellidae insect family, ladybugs are a primarily predatory species of beetle that most commonly have a red shell with black dots but may also be orange, black, pink, yellow, or gray with yellow, red, orange, or white dots or occasionally stripes. These insects are a favorite of gardeners and farmers because they eat several garden pests and their eggs, most famously aphids.
Types of Ladybugs
Also known as "ladybirds" or "lady beetles," there are between 5,000 and 6,000 varieties of ladybugs in the world, with nearly 500 living in North America. The most common species in the U.S. is the seven-spotted ladybug, which is native to Europe and Asia and was imported to North America in the 1950s through the 1970s as a biological pest control option. Though some are concerned that these beetles may be invasive and are outcompeting native ladybugs, Keck believes there are plenty of pests, especially aphids, to maintain sustainable populations of both native and nonnative ladybugs.
Whatever species are native to your region, it's almost always good to have ladybugs in your garden, as they are nearly all predators that eat plant-destroying pests. Many species also serve as pollinators that supplement their diet with nectar and pollen. Ladybugs in the Psyllobora genus help plants even more by eating problematic fungi, like powdery mildew. While a handful of ladybugs, such as the squash beetle and Mexican bean beetle, are herbivores, most ladybugs you see in the garden are beneficial insects and not pests, so avoid harming them unless you are absolutely sure that the species on your plant is damaging it.
The Life Cycle of Ladybugs
"If you start to notice that you're having aphids on a certain plant, take a good look around that plant, and there's a good chance you're going to see some eggs from ladybugs or some young larvae that just hatched," says Keck. Ladybugs generally lay eggs near a food source, typically on the bottom side of leaves. Eggs are usually laid in rows or clusters and may vary in shape, size, and color depending on the species. The most common ladybug egg colors are white, yellow, and orange.
After a few days, a larva will hatch and eat its eggshell and any unhatched eggs nearby. The larvae of different species vary in appearance, but they typically have long, spiky bodies reminiscent of an alligator. The larvae of highly common seven-spotted ladybugs are black with orange, yellow, or red spots. Like adult ladybugs, ladybug larvae eat eggs, larvae, and insects, sucking the juice from prey that is too large for them to swallow. They grow quickly and shed their skin several times before reaching their full size, at which point they attach their tail to a leaf and form a pupa.
After one or two weeks, an adult ladybug will emerge from the pupa. After mating, ladybugs will sometimes lay eggs right away, and sometimes they will overwinter in a state of dormancy, storing sperm throughout the winter so they can lay their eggs in spring when there is more food available. Those who go dormant in the winter may travel far from their current home or overwinter in the same location. Either way, they will hide in a sheltered spot, frequently with other ladybugs, burying themselves in leaf litter, under tree bark, or in thick vegetation. Adult ladybugs live for around one year.
Why Do People Use Ladybugs as Pest Control?
A single adult ladybug can eat around 75 problematic insects daily, meaning they are very good friends for plants. It's no wonder many gardeners want to know what attracts ladybugs to their yard and where to buy live ones. Unfortunately, ladybugs have their disadvantages as a pest control method because as wild creatures, it can be hard to convince them to stay in a particular area. The insects tend to fly away when moved from one location to another, whether the original location was just across your garden or wherever they were harvested from before being placed in a container to be sold in a store.
While Keck is skeptical that a container of ladybugs can eradicate an aphid infestation, she did say that if it is possible to keep them around, you'll need to follow the steps I took to release them. Research from the University of California suggests these releases can effectively control aphids in a small area if the ladybugs are correctly handled. Here's how I encouraged my container of live ladybugs (which I purchased at Lowe's for about $8) to stick around after they were released.
Avoid using pesticides. Most pesticides, with the exception of insecticidal soap and horticultural oil, leave behind residue that can harm beneficial insects like ladybugs. Don't release ladybugs if you've recently sprayed any insecticides and avoid spraying them after releasing your spotted little helpers.
Buy healthy ladybugs. Where you buy ladybugs can impact their health and how many aphids they can eat. When possible, buy directly from a supplier rather than a big-box store, where they may be held for weeks before being purchased. Even those from major retailers can be OK, though, as long as they appear healthy. Inspect the container to ensure most of the ladybugs are active and alive before bringing them home.
Wait until just before dusk. Ladybugs are diurnal, so if you release them just before dark, they'll find a place to sleep for the night rather than flying away.
Put them in the refrigerator first. Cold winter temperatures cause ladybugs to go into a dormant state. While putting them in the refrigerator won't make them go fully dormant, it will make them calm down a little so they won't fly away as soon as the container is opened. "It doesn't take very much —15 minutes is all they need inside the fridge," says Keck.
Water your aphid-infested plant. Ladybugs kept in bags or containers get very thirsty. They'll seek water when they are released, and watering the plant encourages them to stick around for the night.
Sprinkle them by the base of the plants. When I released my ladybugs, I couldn't find any directions about where to place them when you set them free. My son and I tried putting some directly on the plants, but they tended to either fall off the branches or fly away immediately (our body heat helped wake them up). When you place them near the plant's base, they'll climb the branches to fly away in the morning. With any luck, they will then see all the tasty aphids feasting on your plant and decide against leaving.
Spread them around. Ladybugs will leave if there are too many on one plant. Place them around multiple aphid-covered plants in the same area so they can benefit your entire garden. Ladybugs sold in stores are from species that feast primarily on aphids, so they will go elsewhere to find an adequate food supply if your plants have too few aphids.
Release the ladybugs in batches. Try releasing half or a third of the ladybugs in the container every few days. This way, even those that immediately fly away will still eat some aphids on their way out, giving you more bang for your buck. Keep those left in the bag or carton in the refrigerator until you are ready to release them and lightly mist the container each morning using a spray bottle of water.
Don't be discouraged. Ladybugs sold commercially were harvested while hibernating in large groups during winter. Their instinct is to spread out and fly away from the group when the weather warms up. Research shows that 95 percent of the bugs will leave your property within 48 hours, even when you use proper release methods. With any luck, this will be after they've eaten tons of aphids and laid eggs on your bushes, so their babies can continue on your pest control mission. When I released ladybugs, over half left the first day, and though I released multiple batches, within a week, I only had about two stragglers left. While the red and black insects may have left my rose garden quickly, they ingested nearly all of my aphids in the process.
Benefits/Risks of Having Ladybugs in the Garden
Benefits of Ladybugs in the Garden
- Eats pests and harmful fungi
- Won't harm beneficial insects
- Safe for kids
- Can buy them at a garden store
- Add color to a garden
- It's a fun activity
- Considered lucky in some cultures
Risks of Ladybugs in the Garden
- It may take a while for aphids to disappear off your plants
- Purchased ladybugs will fly away
- Ladybugs can be poisonous to pets
- Some species hibernate inside homes
- They may carry diseases or pests
- Some ladybugs may bite or scratch when picked up
- Some individuals may have mild skin allergies to ladybugs
All things in life have pros and cons, but when using ladybugs for your garden, the advantages are many, and the disadvantages are very few. The benefits are pretty easy to see:
- With only a handful of exceptions, ladybugs are good for plants since these predatory insects eat dozens of pests daily. On top of that, many also pollinate plants, and a few even eat harmful fungi on plants.
- Unlike pesticides, they won't harm other beneficial insects in your garden.
- Ladybugs are adored by many children and are safe for kids.
- They're adorable, and their bright red coloring adds a cheerful accent to gardens.
- If you don't have ladybugs in your yard, you can buy them at home improvement stores or gardening centers.
- Releasing them is fun for children.
- Ladybugs are considered lucky in some cultures.
While ladybugs are relatively harmless, there are some potential downsides to using them for pest control:
- Attracting ladybugs naturally means leaving your aphids alone until the good guy bugs appear.
- If ladybugs purchased from the store are not released properly, they will fly away without eating your aphids.
- While not dangerous to humans, ladybugs can be poisonous when ingested by pets.
- Some species, including the Asian lady beetle, hibernate inside homes. While they won't cause damage to your house, they can cause asthma symptoms and allergic reactions.
- Ladybugs harvested to be sold commercially may carry diseases or pests that could harm native populations.
- Some ladybugs may bite or scratch when picked up, but they prefer flying away over attacking. While these bites and scratches may hurt, the insects do not carry diseases and are rarely able to break the skin.
- Some individuals may have mild skin allergies to the odorous substance ladybugs emit to defend themselves, but avoidance merely requires leaving the bugs alone.
Pests That Ladybugs Eat
"I think most people, when they see ladybugs in their landscape, they're seeing them feed on aphids," says Keck. For those unfamiliar, aphids are small, rounded insects that come in various colors, including green, yellow, brown, gray, orange, red, and black. They typically live on new vegetation or the underside of leaves, where they suck juices from the plants, causing them to become stressed, wilted, stunted, or deformed.
While aphids might be the favorite food of most ladybug species, different varieties may also eat other pests, including mites, scale insects, fruit flies, thrips, mealybugs, and tiny caterpillars. They can also eat the eggs of some insects, including the Colorado potato beetle and European corn borer.
How to Encourage Ladybugs in the Garden Naturally
"The only way to attract them is to have aphids," says Keck, which makes sense given that the insects are a favorite food. Of course, giving them a few other foods to snack on doesn't hurt, so you can try planting pollen-heavy for the omnivorous ladybugs. Favorites include marigolds, geraniums, yarrow, angelica, calendula, and dill.
Aside from that, those hoping to cultivate a harmonious relationship with ladybugs should avoid using pesticides, even organic ones. If you must spray insecticides, inspect your plants for ladybug eggs and larvae before use and only use pesticides that kill on contact and don't leave a residue. Keck says that insecticidal soap and horticultural oil are some of the only ladybug-friendly pesticides, though she notes that direct contact will still kill ladybugs.
Alternatively, you can try squishing the aphids, but always check there are no adult ladybugs or their larvae or eggs in the area first. "There's no way to target just the aphids without harming your ladybugs," she warns.
Parasites/Diseases Wild-Caught Ladybugs Carry
Ladybugs do not carry any diseases or parasites that can be passed on to humans. However, wild-caught ladybugs harvested and sold commercially can carry parasites and diseases that may be transmitted to native ladybug populations. Between 3 and 15 percent of these wild-harvested ladybugs carry the internal parasite Dinocampus coccinellae, and many are also infected with microsporidia, a disease that can shorten the ladybug's life span and reduce the number of eggs they lay.
Will ladybugs stay in my garden if I release them?
For the most part, no. Around 95 percent will leave within the first 48 hours, and the rest will typically fly away within five days. With any luck, the ladybugs will still help your plants by munching on your aphid population and laying eggs before they leave.
Can you use ladybugs in a vegetable garden?
Absolutely! “Different species [of aphids] target different things,” says Keck, “so it really runs the gamut from vegetables to ornamentals to trees.” If your vegetable garden has aphids, ladybugs can help eliminate them.
How do you use ladybugs in your garden?
Schedule your ladybug release for dusk. Place the ladybug container in the refrigerator for at least 15 minutes and then water your plants, taking care to spray some aphids off the leaves. Once the plants and insects are prepared, sprinkle one-third to one-half of the container of ladybugs around the base of your plants.
What time of year should I put ladybugs in my garden?
“Spring and summer because that’s when plants are growing,” says Keck. “Depending on where you are, fall can be a great time as well.” She notes that in warmer climates, it might be hard to find live ladybugs in stores late in summer simply because they don’t travel as well in hot temperatures.
How many ladybugs do I need for my garden?
Because many ladybugs will fly away after being released, buy a large quantity of the insects. For a large rose bush with a heavy aphid infestation, the University of California recommends doing two applications a week apart using 1,500 ladybugs each time.