If they eat so many aphids, why would anyone consider them a problem?

Because the same trait that makes them effective against aphids — an aggressive, generalist appetite — extends to the eggs and larvae of other lady beetle species, including natives that used to fill the same ecological role. Being a good aphid predator and being a competitor that displaces other predators aren't contradictory; they're two consequences of the same generalist, high-consumption biology, and the research documents both.

Do ladybugs eat 'Asian beetles' too, since they're supposedly different pests?

That question assumes two separate animals, and there aren't any — Harmonia axyridis is a ladybug, so this isn't a predator-prey relationship between species, it's the same insect. What does happen is intraguild predation among lady beetle species generally: Harmonia axyridis preys on the eggs and larvae of other coccinellids, including native ones, more often than it is preyed upon itself, which is part of why its spread has coincided with native declines.

Should I try to get rid of them if they're helping my garden?

That's a values call this hub doesn't make for you — the honest input is that removing them trades away real aphid control for a reduction in a species that also displaces natives, and neither side of that trade is free. If your actual question is how to reduce a fall aggregation on your house rather than a garden population, that's a seasonal shift worth timing: UNH Cooperative Extension notes these beetles are most numerous on the sunny side of New Hampshire buildings on mild days from mid-September through early November, so sealing entry points before mid-September closes the window before the garden predator becomes a wall nuisance. /top-diy-methods/asian-lady-beetle covers removal in detail; this page exists to state the ecology plainly, not to recommend for or against control.

Are native ladybugs actually disappearing because of Asian lady beetles specifically?

The evidence is strong but not simple. A 31-year Maine potato-field study documented significant native lady beetle declines coinciding with the establishment of alien species, and the near-total disappearance of the nine-spotted lady beetle from 1993 northeastern surveys lines up with Harmonia axyridis's spread. Researchers are careful that causation is multi-factor — habitat change and agriculture play a role too — but the coincidence in timing and the intraguild-predation mechanism are both well documented, not speculation.

Daniel Brady · NH-Licensed Pesticide Applicator · License #782664

Are Asian Lady Beetles Good for My Garden?

Both things are true

Both things are true, and this is the one question in this hub we can't honestly flatten to yes or no. Harmonia axyridis is a voracious, genuinely effective predator of aphids and other soft-bodied garden pests — that reputation is earned, which is exactly why it was deliberately introduced to North America as biological control in the first place. It is also a documented invasive species that outcompetes and preys on native ladybugs, contributing to real, measured declines in species like the nine-spotted lady beetle. Holding both facts at once is the honest answer; picking one half is not.

At a glance

The short answer: Both things are true
How to tell: Behaviour, not colour — see The Split
Where removal lives: We route it out — this hub owns identity

The verdict

One animal, one honest answer

The verdict on Are Asian lady beetles good for my garden?

Both things are trueand we are not collapsing it

It's a genuinely effective aphid predator and a documented invasive that displaces native ladybugs — both are true at once, and neither cancels the other out.

Which one is on your house?

Native ladybug vs. the Asian lady beetle

Two names, one animal. Both columns always render — and they always converge on the same resolution. The tell is behaviour, not colour.

The native ladybug

(the one you're picturing)

Also an aphid predator, but present in the garden in far smaller numbers than it once was in many parts of the Northeast
Does not aggregate on or inside houses to overwinter — it isn't the beetle massing on your siding each fall

The Asian lady beetle

(Harmonia axyridis)

On your house

An adult can eat roughly 90 to 270 aphids a day, and a single larva can consume 600 to 1,200 over its development — a real, deliberately introduced biological-control agent
Colour runs pale yellow-orange to deep red to fully black — colour alone is a weak tell, not a diagnosis, and it says nothing about which garden role you're seeing

Whichever name you use, it's the same insect doing both things in the same garden: eating aphids effectively, and out-competing the native ladybugs that used to do the same job.

Colour is a weak tell, not a diagnosis

Watch a ladybug clear an aphid colony and its shade won't tell you whether you're looking at a native species or the invasive one — both are effective predators, and both can wear nearly identical colours. Iowa State University Extension documents Harmonia axyridis alone spanning pale yellow-orange through deep red to fully black, with anywhere from zero to nearly twenty black spots, and native New Hampshire ladybugs overlap that range. Colour is a weak tell in the garden; only the fall house-aggregation behaviour reliably marks the Asian lady beetle.

Want a real identification key instead of a router? See the species profile.

The full answer

What's actually going on

Yes — it's a genuinely effective predator, and that's not spin

Harmonia axyridis is a generalist predator of aphids and other soft-bodied insects, and the underlying biology is well documented. Per the University of California Statewide IPM Program, because adults can live more than a year, a single individual can consume over 5,000 aphids or similarly sized prey across its larval and adult lifespan; a Cornell/Maine Department of Agriculture, Conservation and Forestry factsheet puts the daily rate at roughly 90 to 270 aphids for an adult and 600 to 1,200 over a larva's full development. This is not incidental — it's frequently the single most abundant predator attacking soybean aphid in North American fields, capable of both preventing and suppressing outbreaks, and a 2016 review in BioControl catalogued numerous documented cases of the species delivering real agricultural benefit, including historical control of pecan aphid complexes and strawberry, rose, and pine-scale infestations (Koch 2003). It was introduced to North America deliberately, more than once, specifically because this predation is real.

Also yes — it's a documented invasive that displaces native ladybugs

The same beetle is a strong intraguild predator and competitor: it preys on the eggs and larvae of other lady beetle species more often than the reverse, and its spread has coincided with sharp declines in natives. Coccinella novemnotata, the nine-spotted lady beetle, was once the most common lady beetle in the northeastern United States and is New York's state insect — comprehensive USDA APHIS surveys across eleven northeastern states in 1993 found none at all, a decline the New York Department of Environmental Conservation and the Xerces Society both track as part of a broader native-ladybug collapse coinciding with Harmonia axyridis's establishment. A 31-year Maine potato-field study (Alyokhin & Sewell 2004) documented significant declines in native lady beetles following the arrival of alien species, and long-term Swiss monitoring found Harmonia axyridis rising to 60 to 80 percent of hedge-ladybird communities while a once-dominant native, the two-spot lady beetle, nearly disappeared. Displacement, alongside effective predation, is the honest second half of this answer — not a footnote to soften.

The short of it

Key takeaways

Both things are true: it's a genuinely effective aphid predator, and a documented invasive that displaces native ladybugs.

An adult can eat roughly 90 to 270 aphids a day; a larva can consume 600 to 1,200 over its development — real, deliberately introduced biological control.

Its spread has coincided with sharp native declines, including the near-disappearance of the nine-spotted lady beetle from the northeastern U.S.

This page replaces 13 of our own legacy pages that asked the beneficial and harmful questions separately instead of holding both at once.

Full transparency

These questions all land here

We asked this more than once, under more than one name, and printed more than one answer. There was only ever one — so here's what this page replaces.

This page replaces 13 of our own pages

Our old site asked whether they help gardens and whether they harm crops as if those were two different animals answering two different questions — including one page asking whether ladybugs eat 'Asian beetles,' a question that dissolves once you know they're the same family. Thirteen pages, one honestly two-sided answer.

are-asian-beetles-harmful-to-plantsare-ladybugs-good-for-gardensare-ladybugs-harmful-or-helpfulcan-asian-beetles-harm-cropsdo-asian-beetles-destroy-cropsdo-asian-beetles-eat-other-insectsdo-ladybugs-come-from-plantsdo-ladybugs-eat-aphids-indoorsdo-ladybugs-eat-asian-beetlesdo-ladybugs-eat-mitesdo-ladybugs-eat-other-bugsdo-ladybugs-eat-plantsdo-ladybugs-help-control-pests

Where this routes

Looking to get rid of them?

This hub answers what it is — not how to remove it. Most people who land here actually want one of these next steps, so we hand you straight to the hub that owns it.

Removal

This hub answers what it is, not how to get rid of it — the actual removal guide lives here.

Go there

Why now — fall invasion timing

What they do all winter

Seasonal activity calendar

Will they damage anything?

Full species profile

Good for the garden, unwelcome on the wall.

Its aphid appetite is real and so is the fall aggregation on your siding — you don't have to pick a side on the ecology to want the second one handled.

Get a Free inspection (603) 785-0118

Follow-up questions

Frequently asked

Sources & further reading(9)

[1]
UC Statewide Integrated Pest Management Program — "Multicolored Asian Lady Beetle"
An adult can consume over 5,000 aphids or similar-sized prey across its larval and adult lifespan
extensionverified 2026-07-17
[2]
Koch 2003 — Journal of Insect Science, "The Multicolored Asian Lady Beetle, Harmonia axyridis: A Review"
Documented biological control of pecan aphid complex, strawberry/rose aphids, and pine scale
academicverified 2026-07-17
[3]
Riddick 2016 — BioControl, "Reaping benefits from an invasive species"
Harmonia axyridis as the most abundant predator of soybean aphid, capable of preventing and suppressing outbreaks
academicverified 2026-07-17
[4]
New York State DEC — Species of Greatest Conservation Need Assessment, Nine-Spotted Lady Beetle
1993 USDA APHIS surveys found no nine-spotted lady beetles across eleven northeastern states
stateverified 2026-07-17
[5]
Xerces Society — Species Profile, Nine-Spotted Lady Beetle
Native lady beetle decline coinciding with the spread of invasive coccinellids
academicverified 2026-07-17
[6]
Roy et al. 2020 — Insects, long-term Swiss ladybird monitoring
Harmonia axyridis rising to 60-80% of hedge ladybird communities while Adalia bipunctata nearly disappeared
academicverified 2026-07-17
[7]
Alyokhin & Sewell 2004 — Biological Invasions, "Changes in a Lady Beetle Community Following the Establishment of Three Alien Species"
31-year Maine potato-field study documenting significant declines in native lady beetles following the arrival of alien species
academicverified 2026-07-22
[8]
Iowa State University Extension — "Ladybug, Multicolored Asian Lady Beetle"
Colour and spot-count variability of Harmonia axyridis
extensionverified 2026-07-17
[9]
UNH Cooperative Extension — Multicolored Asian Ladybug fact sheet
Beetles most numerous on sunny sides of NH buildings mid-September through early November; seal before mid-September
extensionverified 2026-07-17

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

Verify license

Last updated July 2026

Honest pest ecology for New Hampshire homes

Thirteen Pages, One Two-Sided Answer

It's a real aphid predator and a real threat to native ladybugs — both are true, and we're not going to pretend otherwise to make a tidier headline. Family-owned since 2017, NH license #782664, based at 700 Harvey Rd in Manchester.