Ladybugs in the Garden: Predators, Limits, and How to Keep Them
Kelly Smith Trimble brings practical gardening knowledge and experience explaining how plants grow and thrive. Her interests include vegetable growing, seasonal garden care, and the everyday decisions that help gardeners make the most of their outdoor spaces.
Quick answer
Yes, ladybugs are good for gardens because they eat aphids, mites, and scale insects. They protect vegetables, flowers, and fruit crops from these pests. Both adults and larvae hunt and eat soft-bodied bugs. Wild ladybugs work better than bought ones. Bought ladybugs almost always fly away before they do much good.
What Makes Ladybugs Valuable Predators
Ladybugs — also called lady beetles or ladybird beetles — are among the most effective natural pest controllers you can have in a garden. Both the adult beetles and their larvae have chewing mouthparts. They hunt soft-bodied insects throughout the growing season. Colorado State University Extension says they eat aphids, scales, spider mites, and mealybugs. They also feed on almost any small insect egg they can attack.
The Cornell University biological control program notes that over 450 lady beetle species are found in North America, and most are beneficial as both adults and larvae. Because they can survive on pollen, nectar, and other small prey when aphids are scarce, they stick around even when pest pressure is low — making them particularly valuable as long-term garden residents.
How Much Do They Actually Eat?
The numbers are striking. The convergent lady beetle may eat its weight in aphids every day as a larva. Hippodamia convergens is its scientific name. As an adult, it can eat as many as 50 aphids per day. The sevenspotted lady beetle does even more. Adults may eat several hundred aphids per day. Each larva eats 200 to 300 aphids as it grows.
This difference between larvae and adults matters for your garden. Larvae are often the bigger pest controllers — they cannot fly away and must keep eating to develop. Adults are mobile and may leave once local prey runs low. If you spot the alligator-like, dark-spotted larvae on your plants, that is a sign active pest control is happening right now.
Two Species That Harm Plants, Not Pests
Not every ladybug-looking beetle is your ally. Two species actually damage plants instead of helping. The Mexican bean beetle and the squash beetle both feed on plants rather than pests. Their scientific names are Epilachna varivestis and Epilachna borealis. Colorado State University Extension confirms the Mexican bean beetle feeds on bean foliage and developing pods. It is an important pest of beans.
You can tell these apart from beneficial species: Epilachna beetles tend to be larger, more yellowish-orange, and heavily spotted, and you will find them chewing leaf tissue rather than hunting insects. If you see a ladybug-shaped beetle on your bean plants and the leaves show skeletonized damage, check the species before assuming it is helping.
Purchased Lady Beetles vs. Wild Ones: Why Wild Wins
Many garden centers sell convergent lady beetles for aphid control, but the track record is poor. Colorado State University Extension explains two reasons. First, field-collected beetles are highly dispersive — they are poised to migrate long distances from their collection sites, and with few exceptions, you should expect released beetles to fly away from your garden. Second, these beetles are usually in a state called reproductive diapause — a temporary suspension of egg-laying — and will not produce eggs until they have fed for several weeks after release.
UC IPM confirms this: released lady beetles may give some temporary control when properly handled, but most disperse within a few days. One UC research example found that a single heavily infested rose bush required two applications of about 1,500 beetles each, spaced a week apart — a high cost for uncertain results. Sellers of purchased lady beetles may have a commercial interest in promoting their effectiveness, so weigh that when reading product claims.
If you do release purchased beetles, UC IPM gives a few tips. Keep them refrigerated until just before release. Let them go at dusk. Mist them with water beforehand. Place them at the base of infested plants rather than scattering them broadly.
How to Attract and Keep Native Lady Beetles
Supporting wild, naturally occurring lady beetles is far more effective than buying them. Colorado State University Extension outlines three practical steps.
- Plant shallow flowers. Lady beetles visit flowers for nectar and pollen, and they need blooms with accessible mouthparts. Dill, coriander, and alyssum are good choices that fit this profile.
- Tolerate a low level of aphids. Lady beetles need prey to stay in your garden. A small aphid population on a non-critical plant gives them a reason to linger and lay eggs nearby. Cornell’s resources note that early-season populations often build up on aphid-infested perennials or shrubs before moving to vegetable beds.
- Leave overwintering shelter. Cornell notes that lady beetle adults benefit from nearby shelter — leaf litter, bark, and dense perennial clumps — for protection from weather and as overwintering sites. Avoid clearing every corner of the yard in fall.
Controlling ants is also worth doing. Ants tend aphid colonies for honeydew and actively drive off lady beetles and other predators. Colorado State University Extension notes that by controlling ants, lady beetle activity can increase in many cases. You can learn more about natural aphid control methods that work alongside beneficial insects.
Which Pesticides Are Safe Around Lady Beetles
Broad-spectrum insecticides are the biggest threat to lady beetle populations in home gardens. UC IPM advises avoiding them because they harm natural enemies. Some options are largely safe for lady beetles, as long as the beetles are not directly sprayed. Colorado State University Extension lists these safer choices: insecticidal soaps, horticultural oils, pyrethrum, and neem. Bacillus thuringiensis (Bt) products do not affect lady beetles at all.
Systemic insecticides are a different matter. They are much more toxic and may harm bees and other beneficial insects on flowering plants. In California, these materials are only available to licensed pest control professionals. Always read the product label before applying any pesticide. The label gives the legal application rate, target pests, and safety intervals. For a broader look at how to sequence these decisions, see how the integrated pest management four-step system works.
The Multicolored Asian Lady Beetle: Helpful but Occasionally a Nuisance
One species deserves a separate note. The multicolored Asian lady beetle (Harmonia axyridis) was introduced to North America to control aphids on fruit and nut crops and has proved to be an important aphid predator on trees and shrubs. Colorado State University Extension reports it has steadily expanded its range and is now found across much of the country.
The downside: this species often uses buildings for overwintering shelter. Large masses appear in fall — sometimes called “Halloween beetles” for their timing and bright color. Inside a home, they are largely harmless, but they can produce a mildly disagreeable odor when disturbed. If they are entering your home, seal gaps around windows, doors, and utility penetrations before fall. Do not spray them indoors with broad-spectrum pesticides, which would also harm any beneficial insects nearby.
Frequently asked questions
Do ladybug larvae look different from adults, and are they also beneficial?
Yes — larvae look nothing like adults. They are elongated, dark, and alligator-like with prominent legs and yellow or orange spots. Both stages are predatory. Larvae are often the more active pest controllers because they cannot fly away and must keep eating to grow. Cornell's biological control resources note larvae grow through four instars over a 20 to 30 day period, consuming large numbers of aphids throughout.
Will lady beetles eat anything other than aphids if aphids run out?
Yes. When aphids are scarce, lady beetles will feed on moth and beetle eggs, mites, thrips, and other small insects. They also eat pollen and nectar. This flexibility is one reason they are considered valuable natural enemies. They can stay in a garden even when pest pressure is temporarily low.
Can I accidentally kill lady beetles with the pesticides I use for other pests?
Easily, yes. Broad-spectrum insecticides are toxic to lady beetles. Colorado State University Extension notes that soaps, horticultural oils, pyrethrum, neem, and Bt products are largely safe for lady beetles as long as the beetles are not directly sprayed. Always check the label and avoid spraying when lady beetles or other beneficial insects are visibly active on plants.
How do I tell a Mexican bean beetle apart from a beneficial ladybug?
Look at what it is doing and where. The Mexican bean beetle feeds on bean foliage and pods, leaving skeletonized leaf damage. Colorado State University Extension describes it as a plant-feeding species — not a predator. Beneficial lady beetles will be found hunting insects on stems and leaves, not chewing plant tissue. The Mexican bean beetle also tends to be more yellowish-orange and heavily spotted compared to common red predatory species.
Is there a best time of year to encourage lady beetles in the garden?
Late spring through early fall is when most lady beetle species are actively feeding and laying eggs. Many species have one generation per year, timed with the spring flush of aphids. Planting nectar flowers like dill and alyssum early in the season gives adults a food source before aphid populations build. This helps them stay in your garden when pest pressure rises.
Sources
- Aphids / Home and Landscape / UC Statewide IPM Program (UC IPM) · ipm.ucanr.edu
- Lady Beetles | Colorado State University Extension · Colorado State University Office of Engagement and Extension (extension.colostate.edu)
- Lady Beetles · biocontrol.entomology.cornell.edu
Prepared from these references and checked against them. References retrieved October 11, 2026.
Spotted an error? Tell us what needs correcting.