Scarlet lily beetle (Lilioceris lilii)

Synonyms: Attelabus lilii, Crioceris lilii

Common Names: lily leaf beetle, red lily beetle, lily beetle

Description:

Scarlet lily beetle (Lilioceris lilii) is a bright red, invasive beetle from Europe and Asia that feeds on true lilies and fritillaries [1]. It reached North America on imported lily bulbs ? Montreal in 1945, then the United States in 1992 ? and has spread across the continent, reaching Michigan in 2016 [6][8]. MISIN tracks it because both the adults and their larvae can quickly strip garden lilies and threaten Michigan's native wild lilies [3].

Identification:

The adult is a striking, shiny scarlet-red beetle about a quarter-inch long (6 to 9 mm), with a black head, legs, and antennae and a black underside [1][2]. The larvae look very different: soft, plump, and slug-like, with orange to brownish bodies and black heads. They carry a wet pile of their own dark droppings on their backs, which makes an infested plant look like it is smeared with mud [2][8]. Eggs are tiny and reddish-orange and sit in uneven rows on the undersides of leaves [2].

This beetle is easiest to find in spring, from the moment lily shoots break through the ground into early summer ? the bright red adults stand out against fresh green leaves [1][2]. Look on and under the leaves for adults, egg rows, and frass-covered larvae. When you reach for an adult, it often drops straight to the ground and lies still on its dark underside to hide [1].

At-a-glance cues:

1. Shiny scarlet-red adult about a quarter-inch long, with a black head and legs [1][2]
2. Slug-like larvae carry a wet pile of their own black droppings on their backs [2][8]
3. Reddish-orange eggs in uneven rows on the undersides of lily leaves [2]
4. Found on true lilies and fritillaries; a disturbed adult drops to the ground and plays dead belly-up [1]

Hosts:

The scarlet lily beetle lives wherever true lilies grow ? home gardens, yards, plant nurseries, and natural areas, including woodland edges where native wild lilies bloom [1][8]. It is native to Europe and Asia [1].

The beetle only lays its eggs and completes its life cycle on true lilies (Lilium species) and fritillaries (Fritillaria species). These include garden favorites like tiger, Easter, Asiatic, and Oriental lilies, as well as native wild lilies such as Canada lily, wood lily, and Turk's cap lily [1][3]. Adults will also nibble on a few other plants without breeding on them ? lily of the valley, Solomon's seal, hosta, bittersweet nightshade, potato, and hollyhock [1][2]. Plants with "lily" in their name but that are not true lilies ? daylilies, canna lilies, and calla lilies ? are not at risk [1][8].

Adults spend the winter tucked into soil, leaf litter, and garden debris, often in shaded, cool, moist spots and not necessarily near the plants they feed on [1][2]. Studies of climate suitability suggest much of temperate North America offers good conditions for the beetle, so its range is expected to keep growing [7].

Life Cycle:

The most common way this beetle reaches a new yard is by hitchhiking on infested lily bulbs and potted nursery plants moved from place to place ? the same path that first carried it across the ocean and that keeps spreading it today [6][8]. Adults can also fly to nearby lilies on their own.

There is one generation each year. Adults spend the winter in soil and debris and become active in spring as soon as lily shoots appear [1][2]. Females lay eggs in uneven rows on the undersides of leaves, usually in May, and a single female can lay 250 to 450 eggs over her life [1][2]. The eggs hatch in about 4 to 8 days. The larvae then feed for two to three weeks ? this is the most destructive stage ? before dropping into the soil to pupate; new adults appear two to three weeks later in summer and can live for more than a year [1][2].

This timing is the key to control. Check plants the moment lily shoots emerge, and remove adults and egg rows before the larvae hatch ? wiping out the reddish egg rows in May heads off the worst feeding [2][8].

Impact and Damage:

For a gardener, the damage is quick and obvious. Both the adults and the larvae chew irregular holes and notches in leaves, stems, and flower buds, and heavy feeding can strip a lily bare and destroy its blooms [1][2]. Feeding early in the season produces undersized bulbs that may not flower the next year, so a lily bed can be lost over a couple of seasons [1]. The larvae, coated in their own droppings, are also unpleasant to pick off by hand [2].

Beyond the garden, the bigger concern is North America's native wild lilies. Lab and field research shows the beetle readily lays eggs and develops on native species such as Canada lily, wood lily, and Turk's cap lily, and here it has no native predators or parasites to keep it in check [3][4]. Where wild lilies are attacked year after year, local stands can be worn down [3]. Climate modeling indicates the beetle could spread across much of temperate North America, widening the area where native lilies are at risk [7].

The beetle is also a costly pest for the lily nursery and cut-flower trade, where infested plants must be controlled or destroyed before sale [1].

Similar species:

No look-alikes are tracked for this species in the MISIN system yet. Several red or red-and-black beetles are mistaken for the scarlet lily beetle:

Seven-spotted lady beetle (Coccinella septempunctata) is the most common mix-up because it is also small and red. It is told apart by its black spots and dome-shaped body, while the lily beetle is solid bright red with no spots, a longer oval body, and a black head ? and it is almost always found on lily plants [1][2].

Red milkweed beetle (Tetraopes tetrophthalmus) is red like the lily beetle but carries several black spots and has very long antennae. It feeds on milkweed, not lilies, which makes the host plant a quick way to tell them apart [2].

Asparagus beetle (Crioceris asparagi) is a close relative with the same slender, leaf-beetle shape, but it is dark with cream-colored spots and reddish edges rather than solid red, and it lives on asparagus [1].

Monitoring and rapid response:

Signs to watch for:

1. Bright red adult beetles on lily and fritillary shoots in spring [1][8]
2. Reddish-orange eggs in uneven rows on the undersides of leaves [2]
3. Slug-like larvae covered in black droppings, with chewed, notched leaves and buds in late spring and early summer [2][8]

What you can do:

1. Check lilies and fritillaries every few days from the moment shoots emerge in spring through early summer [1][8].
2. Handpick adults into a container of soapy water. Because a disturbed beetle drops and plays dead, hold a cup or hand underneath before you grab so it cannot fall and hide [1].
3. Wipe off or crush the reddish egg rows on leaf undersides before they hatch ? best in May ? to stop the damaging larval stage [2][8].
4. Remove and bag the frass-covered larvae you find [2].
5. For a natural area crew: sweep garden lilies and native wild-lily stands on a repeated schedule through spring, focusing first on protecting native lily populations and clearing beetles before the larvae mature. Limiting soil disturbance and mulching around known sites helps protect introduced parasitoid wasps where they are present [4][5].

When to call a professional:

1. Large nursery or display plantings, or repeated heavy infestations that outpace handpicking [1].
2. Sites where protecting rare native lilies is the priority ? a land manager can plan a coordinated, multi-visit response [4].
3. Biological control with introduced parasitoid wasps has reduced beetle damage in parts of the Northeast; it is run through research programs, not by home release [4][5].
4. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. Utah State University Extension. Lily Leaf Beetle (Lilioceris lilii Scopoli). extension.usu.edu
2. UMass Amherst Center for Agriculture, Food, and the Environment. Lily Leaf Beetle, Lilioceris lilii. umass.edu
3. Ernst CM, Cappuccino N, Arnason JT (2007). "Potential novel hosts for the lily leaf beetle Lilioceris lilii Scopoli (Coleoptera: Chrysomelidae) in eastern North America." Ecological Entomology 32(1):45?52. semanticscholar.org
4. University of Rhode Island Biocontrol Laboratory. Lily Leaf Beetle. web.uri.edu
5. Tewksbury L, Casagrande RA, Cappuccino N, Kenis M (2017). "Establishment of Parasitoids of the Lily Leaf Beetle (Coleoptera: Chrysomelidae) in North America." Environmental Entomology 46(3):226?236. semanticscholar.org
6. Dieni A, Brodeur J, Turgeon J (2016). "Reconstructing the invasion history of the lily leaf beetle, Lilioceris lilii, in North America." Biological Invasions 18(1):31?44. semanticscholar.org
7. Freeman M, Looney C, Orlova-Bienkowskaja M, Crowder DW (2020). "Predicting the Invasion Potential of the Lily Leaf Beetle, Lilioceris lilii Scopoli (Coleoptera: Chrysomelidae), in North America." Insects 11(9):560. semanticscholar.org
8. Michigan State University Extension. Lily leaf beetles continue to spread in Michigan. canr.msu.edu

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