The scarlet lily beetle, red lily beetle, or lily leaf beetle (''Lilioceris lilii''), is a

leaf beetle The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle ...

that eats the leaves, stem, buds, and flowers, of

lilies ''Lilium'' () is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much of the world. M ...

, fritillaries and other members of the family

Liliaceae The lily family, Liliaceae, consists of about 15 genera and 610 species of flowering plants within the order Liliales. They are monocotyledonous, perennial, herbaceous, often bulbous geophytes. Plants in this family have evolved with a fair ...

. It lays its

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

most often on ''Lilium'' and ''Fritillaria'' species. In the absence of ''Lilium'' and ''Fritillaria'' species, there are fewer eggs laid and the survival rate of eggs and

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e is reduced. It is now a pest in most

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

climates where lilies are cultivated.

Description

This lily beetle belongs to the order

Coleoptera Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

, and the family

Chrysomelidae The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle ...

, the leaf beetles. The adult lily beetle is about 6 to 9 mm (¼–⅜ in) in length, with relatively long legs and antennae. Its

elytra An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes alterna ...

(harder forewings) are bright scarlet and shiny. Its underside, legs, eyes, antennae and head are all black. It has large eyes, a slim thorax, and a wide abdomen.Ernst, C
The Lily Leaf Beetle (''Lilioceris lilii''): an unwelcome invader.
2005 NALS Yearbook. North American Lily Society. pp. 29-34. Retrieved 2012-08-21. Each

antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...

is made up of 11 segments. The

eyes Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conve ...

are notched and there are two grooves on the thorax. This lily beetle may be confused with the

cardinal beetle The name cardinal beetle typically refers to three different species of beetles. The red-headed or 'common' cardinal beetle ('' Pyrochroa serraticornis'') is a red to orange beetle with, as the name suggests, a red head. It is about long, and is ...

(''Pyrochroa serraticornis''), which also has red elytra and a black underside. The wing cases of the lily leaf beetle are dimpled and are shinier and more rounded than those of the cardinal beetle, which are relatively dull, and narrower, flatter, and more elongated. The cardinal beetle also has comb-like antennae. The lily leaf beetle is

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

, while the cardinal beetle preys on insects. The lily leaf beetle is also confused with unspotted

ladybirds Coccinellidae () is a widespread family of small beetles ranging in size from . They are commonly known as ladybugs in North America and ladybirds in Great Britain. Some entomologists prefer the names ladybird beetles or lady beetles as they ...

, but it is narrower in shape.

Natural history

Distribution

The lily leaf beetle is indigenous to parts of Europe and Asia. It is thought to have been introduced to North America through the importation of plant bulbs in 1943. First spotted in

Montreal Montreal ( ; officially Montréal, ) is the List of the largest municipalities in Canada by population, second-most populous city in Canada and List of towns in Quebec, most populous city in the Provinces and territories of Canada, Canadian ...

, it spread throughout Canada and appeared in Massachusetts in 1992, and by 2012 was in all six New England States, as well as New York and Washington states. In

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

it is found from the

Maritime Provinces The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% of Ca ...

west to

Manitoba Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population o ...

. As of 2001, it spread as far west as Alberta, and as of 2017 full infestations reported as far north as the Edmonton, AB area. It has also become established as an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

in the United Kingdom since being first recorded in 1839, although the first colony did not become established until 1939 and it did not spread far until the 1980s, then more rapidly from the 1980s. Since then it has spread from Surrey in southern England as far north as Inverness, Scotland. It is also found in Ireland. It is also found in the Middle East and North Africa.

Life cycle

The beetle overwinters in the

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...

and emerges early in spring. The adult is generally found in moist, cool environments.Lily Leaf Beetle ''Lilioceris lilii''.
University of Rhode Island Landscape Horticulture Program Factsheets. 2002. Retrieved 2012-08-21. It emerges in spring to feed and mate. The female can lay up to 450 eggs each season in batches of about 12 on the undersides of leaves. It arranges the red-orange to brown eggs in narrow irregular lines along the midrib, where they are more concealed. The eggs then hatch into yellow, brown or orange larvae in about 1–2 weeks. The larvae feed for up to 24 days, beginning underneath the leaf then working up the rest of the plant, and cause the most damage. Their preferred feeding locale is underneath the leaf or at the node where the leaf meets the stem. They then burrow in the ground to

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...

te in a cocoon of soil bound with saliva. In about 20 days they emerge as adults and continue to feed until winter. More than one cycle can occur in one year.

Behaviour

Often the first evidence of lily leaf beetle infestation is sticky brown

frass Frass refers loosely to the more or less solid excreta of insects, and to certain other related matter. Definition and etymology ''Frass'' is an informal term and accordingly it is variously used and variously defined. It is derived from the ...

piles containing larvae on leaves. The larvae remain in the frass for protection from the sun and predators. However, the

fecal shield The fecal shield is a structure formed by the larvae of many species of beetles in the leaf beetle family, Chrysomelidae.Nogueira-de-Sá, F. and J. R. Trigo. (2002)Do fecal shields provide physical protection to larvae of the tortoise beetles ''Pl ...

is not effective protection against

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

s, and it may actually make it easier for parasitoids such as the

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...

'' Lemophagus pulcher'' to locate the larvae.Schaffner, U. and C. Muller. 2001
Exploitation of the fecal shield of the lily leaf beetle, ''Lilioceris lilii'' (Coleoptera: Chrysomelidae), by the specialist parasitoid ''Lemophagus pulcher'' (Hymenoptera: Ichneumonidae).
''Journal of Insect Behavior'' 14(6): 739-57. An adult that senses danger displays a defense mechanism,

thanatosis Apparent death, colloquially known as playing dead, feigning death, or playing possum, is a behavior in which animals take on the appearance of being dead. It is an immobile state most often triggered by a predatory attack and can be found in a ...

, becoming motionless, folding up its

appendages An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body. In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including anten ...

and falling with its black under surface facing up, thereby helping it camouflage with the ground to get away. If unable to escape, they are also able to ‘squeak’, by rubbing two parts of their body together, which may be used to startle the attacker. This process is known as

stridulation Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mech ...

and could even shock a bird or any other predator that may attack the lily leaf beetle. Lilies may first show evidence of holes chewed in the leaves from consumption, and if left unchecked rapidly progress to blackening, and total loss of the leaves, leaving only the stem. Beetles and their larvae may also inhabit and devour the developing flower buds. Invasion may occur shortly after the new plants emerge from the soil, particularly if there are nearby ''Fritillaria'' which emerge earlier than ''Lilium''. While ''

Lilium ''Lilium'' () is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much of the world. M ...

'' and ''

Fritillaria ''Fritillaria'' (fritillaries) is a genus of spring flowering herbaceous bulbous perennial plants in the lily family (Liliaceae). The type species, ''Fritillaria meleagris'', was first described in Europe in 1571, while other species from the ...

'' are affected, ''

Hemerocallis A daylily or day lily is a flowering plant in the genus ''Hemerocallis'' , a member of the family Asphodelaceae, subfamily Hemerocallidoideae. Despite the common name, it is not in fact a lily. Gardening enthusiasts and horticulturists have long ...

'' is not. All types of lily may be affected, but while Asiatic lilies are the most vulnerable, some Oriental lilies may be more resistant. Resistant types include ''

Lilium henryi ''Lilium henryi'' (), sometimes called tiger lily or Henry's lily, is a native lily of the mountains of central China (Provinces of Guizhou, Hubei, Jiangxi). The flowers are orange, spotted black, and unscented. The petals are recurving (bent ba ...

'' 'Madame Butterfly', '' Lilium speciosum'' 'Uchida', and ''Lilium'' 'Black Beauty'. Other garden plants affected include ''

Convallaria majalis Lily of the valley (''Convallaria majalis'' (), sometimes written lily-of-the-valley, is a woodland flowering plant with sweetly scented, pendent, bell-shaped white flowers borne in sprays in spring. It is native throughout the cool temperate N ...

'', ''

Polygonatum ''Polygonatum'' , also known as King Solomon's-seal or Solomon's seal, is a genus of flowering plants. In the APG III classification system, it is placed in the family Asparagaceae, subfamily Nolinoideae (formerly the family Ruscaceae). It ha ...

'', potato (''

Solanum tuberosum The potato is a starch#Food, starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial plant, perennial in the nightshade family Solanaceae. Wild potato species can be fo ...

''), flowering tobacco (''

Nicotiana ''Nicotiana'' () is a genus of herbaceous plants and shrubs in the Family (biology), family Solanaceae, that is Native plant, indigenous to the Americas, Australia, Southwestern Africa and the South Pacific. Various ''Nicotiana'' species, common ...

''), hollyhock (''

Alcea ''Alcea'' is a genus of over 80 species of flowering plants in the mallow family Malvaceae, commonly known as the hollyhocks. They are native to Asia and Europe. The single species of hollyhock from the Americas, the streambank wild hollyhock, ...

'') and ''

Hosta ''Hosta'' (, syn. ''Funkia'') is a genus of plants commonly known as hostas, plantain lilies and occasionally by the Japanese name gibōshi. Hostas are widely cultivated as shade-tolerant foliage plants. The genus is currently placed in the fa ...

''.

Pest impact

'' and ''

'' specimens in Canadian gardens, particularly around Halifax, Nova Scotia are significantly affected by the lily leaf beetle. A garden in

Waverley Waverley may refer to: Arts and entertainment * ''Waverley'' (novel), by Sir Walter Scott ** ''Waverley'' Overture, a work by Hector Berlioz inspired by Scott's novel * Waverley Harrison, a character in the New Zealand soap opera ''Shortland Stree ...

Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...

has reported decline of lily species and

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

s from 50 in 1996 to only one in 2006.

Control

The most surefire strategy for preventing infestation by any pest is to avoid planting susceptible plants in the first place, with lily beetle this necessitates avoiding growing so many desirable cultivars of ''Lilium'', that other strategies may be preferred. Regular handpicking and crushing of eggs, larvae and adults is effective if somewhat laborious. Domestic insecticides registered for general leaf beetle control containing

carbaryl Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid previously sold under the brand name Sevin, which was a trademark of the Bayer Company. The Sevin tradem ...

methoxychlor Methoxychlor is a synthetic organochloride insecticide, now obsolete. Usage Methoxychlor was used to protect crops, ornamentals, livestock, and pets against fleas, mosquitoes, cockroaches, and other insects. It was intended to be a replacement ...

malathion Malathion is an organophosphate insecticide which acts as an acetylcholinesterase inhibitor. In the USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa as mercaptothion. Pesticide use Malathion is a pesti ...

and

rotenone Rotenone is an odorless, colorless, crystalline isoflavone used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the seeds and stems of several plants, such as the jicama vine plant, and the roots of several member ...

can prove useful in controlling populations. However,

and

, effective on adults and larvae, are toxic to bees and other insects, respectively. Products based on

neem ''Azadirachta indica'', commonly known as neem, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of two species in the genus ''Azadirachta'', and is native to the Indian subcontinent and most of the countries in Afr ...

extracts are useful in killing very young larvae and repelling adults without comparable harm to other insects, although this option is perhaps less effective than handpicking. Neem products should be applied every 5 to 7 days after egg hatch.

Thiacloprid Thiacloprid is an insecticide of the neonicotinoid class. Its mechanism of action is similar to other neonicotinoids and involves disruption of the insect's nervous system by stimulating nicotinic acetylcholine receptors. Thiacloprid was develop ...

is also effective. Floating

row cover In agriculture and gardening, row cover is any transparent or semi-transparent flexible material, like fabric or plastic sheeting, used as a protective covering for plants, usually vegetables. Covers are used to extend growing seasons, and redu ...

has been effective in preventing the adults from feeding and laying eggs in the spring.

Biological control

In Europe, total parasitism rate in the last instar stage averages about 90% on wild ''

Lilium martagon ''Lilium martagon'', the martagon lily or Turk's cap lily, is a Eurasian species of lily. It has a widespread native region extending from Portugal east through Europe and Asia as far east as Mongolia. Description It is stem-rooting, growing be ...

'', 75% in gardens and 60% in cultivated lily fields. Most lily leaf beetle

parasitoids In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasi ...

are

wasps A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. T ...

that lay eggs inside the host and effectively kill all infected individuals. ''Diaparsis jucunda'' (

Ichneumonidae The Ichneumonidae, also known as the ichneumon wasps, Darwin wasps, or ichneumonids, are a family (biology), family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 2 ...

: Tersilochinae), dominates over 90% of the parasitoid infections in lily leaf beetle. However, in gardens and commercial fields, ''Tetrastichus setifer'' (

Eulophidae The Eulophidae are a large family of hymenopteran insects, with over 4,300 described species in some 300 genera. The family includes the genus ''Elasmus'', which used to be treated as a separate family, "Elasmidae", and is now treated as a subf ...

: Tetrastichinae) and ''Lemophagus pulcher'' (

Campopleginae Campopleginae is a large subfamily of the parasitoid wasp family Ichneumonidae with a world-wide distribution. Species in this subfamily have been used in the biological control of the alfalfa weevil, clover weevil, various species of '' Helioth ...

) become the dominant parasitoids in the later season. There are no natural predators or parasites of lily leaf beetle in North America. In 1996,

University of Rhode Island The University of Rhode Island (URI) is a public land-grant research university with its main campus in Kingston, Rhode Island, United States. It is the flagship public research as well as the land-grant university of the state of Rhode Island ...

began testing the effectiveness of biological control of lily leaf beetle using six natural parasitoids from Europe.

CAB International CABI (legally CAB International, formerly Commonwealth Agricultural Bureaux) is a nonprofit intergovernmental development and information organisation focusing primarily on agricultural and environmental issues in the developing world, and the c ...

Bioscience Switzerland Center has also participated in this project from 1998 till 2001. The European parasitoid wasp ''Tetrastichus setifer'' was used in

Massachusetts Massachusetts (Massachusett language, Massachusett: ''Muhsachuweesut assachusett writing systems, məhswatʃəwiːsət'' English: , ), officially the Commonwealth of Massachusetts, is the most populous U.S. state, state in the New England ...

from 1999 to 2001; the experiment showed reduction of the beetle population. Population decline was also observed at another experiment site in

Rhode Island Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...

. In 2003, another parasitoid, ''Lemophagus errabundus'', was released in

and is now established in the region. Similar parasitoid releases have been made in

Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...

with positive results.

References

Bibliography

External links

Royal Horticultural Society: Lily beetle

see also
{{DEFAULTSORT:Scarlet Lily Beetle Criocerinae Beetles of Europe Beetles described in 1763 Insect pests of ornamental plants Taxa named by Giovanni Antonio Scopoli