Scarlet Lily Beetle
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The scarlet lily beetle, red lily beetle, or lily leaf beetle (''Lilioceris lilii''), is a
leaf beetle The beetle family Chrysomelidae, commonly known as leaf beetles, includes over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making it one of the largest and most commonly encountered of all beetle families. Numerous s ...
that eats the leaves, stem, buds, and flowers, of lilies, 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 fai ...
. It lays its eggs 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 (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...
e is reduced. It is now a pest in most
temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...
climates where lilies are cultivated.


Description

This lily beetle belongs to the order
Coleoptera Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
, and the family
Chrysomelidae The beetle family Chrysomelidae, commonly known as leaf beetles, includes over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making it one of the largest and most commonly encountered of all beetle families. Numerous s ...
, the leaf beetles. The adult lily beetle is about in length, with relatively long legs and antennae. Its
elytra An elytron (; ; : elytra, ) 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 (sometime ...
(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 is made up of 11 segments. The
eyes An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...
are notched and there are two grooves on the thorax. This lily beetle may be confused with the cardinal beetle (''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 evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...
, while the cardinal beetle preys on insects. The lily leaf beetle is also confused with unspotted ladybirds, 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 is the List of towns in Quebec, largest city in the Provinces and territories of Canada, province of Quebec, the List of the largest municipalities in Canada by population, second-largest in Canada, and the List of North American cit ...
, 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 Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
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 ...
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 ...
. 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 is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...
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, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
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 (; : 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 life cycle, the stages th ...
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 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 ...
'' 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, 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 such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface app ...
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 plant, herbaceous flowering plants growing from bulbs, all with large and often prominent flowers. Lilies are a group of flowering plants which are important in culture and literature in much of the world ...
'' and ''
Fritillaria ''Fritillaria'' (fritillaries) is a genus of spring flowering herbaceous bulbous perennial plants in the lily family (biology), family (Liliaceae). The type species, ''Fritillaria meleagris'', was first described in Europe in 1571, while other ...
'' are affected, '' Hemerocallis'' 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'' 'Madame Butterfly', '' Lilium speciosum'' 'Uchida', and ''Lilium'' 'Black Beauty'. Other garden plants affected include '' Convallaria majalis'', ''
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 starchy tuberous vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are underground stem tubers of the plant ''Solanum tuberosum'', a perennial in the nightshade famil ...
''), 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'') and ''
Hosta ''Hosta'' (, synonym (taxonomy), 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 placed ...
''.


Pest impact

''
Fritillaria ''Fritillaria'' (fritillaries) is a genus of spring flowering herbaceous bulbous perennial plants in the lily family (biology), family (Liliaceae). The type species, ''Fritillaria meleagris'', was first described in Europe in 1571, while other ...
'' and ''
Lilium ''Lilium'' ( ) is a genus of Herbaceous plant, herbaceous flowering plants growing from bulbs, all with large and often prominent flowers. Lilies are a group of flowering plants which are important in culture and literature in much of the world ...
'' specimens in Canadian gardens, particularly around Halifax, Nova Scotia are significantly affected by the lily leaf beetle. A garden in Waverley,
Nova Scotia Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...
has reported decline of lily species and
cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...
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. Union Carbide disc ...
,
methoxychlor Methoxychlor is a synthetic organochloride insecticide, now obsolete. Tradenames for methoxychlor include ''Chemform'', ''Maralate'', ''Methoxo'', ''Methoxcide'', ''Metox'', and ''Moxie''. Usage Methoxychlor was used to protect crops, ornamental ...
,
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. The compound's name is presumably ...
and
rotenone Rotenone is an odorless, colorless, crystalline isoflavone. It occurs naturally in the seeds and stems of several plants, such as the jicama vine, and in the roots of several other members of the Fabaceae. It was the first-described member of the ...
can prove useful in controlling populations. However,
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. The compound's name is presumably ...
and
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. Union Carbide disc ...
, effective on adults and larvae, are toxic to bees and other insects, respectively. Products based on
neem ''Azadirachta indica'', commonly known as neem, margosa, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of the two species in the genus '' Azadirachta''. It is native to the Indian subcontinent and to parts of S ...
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 is also effective. Floating row cover 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'', 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 (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...
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. Th ...
that lay eggs inside the host and effectively kill all infected individuals. ''Diaparsis jucunda'' (
Ichneumonidae The Ichneumonidae, also known as ichneumon wasps, ichneumonid wasps, ichneumonids, or Darwin wasps, are a family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 25 ...
: Tersilochinae), dominates over 90% of the parasitoid infections in lily leaf beetle. However, in gardens and commercial fields, ''Tetrastichus setifer'' (
Eulophidae The Eulophidae is 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 subfa ...
: Tetrastichinae) and ''Lemophagus pulcher'' (
Eulophidae The Eulophidae is 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 subfa ...
: Campopleginae) 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 Rhode Island. The univer ...
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 ...
Bioscience Switzerland Center has also participated in this project from 1998 till 2001. The European parasitoid wasp '' Tetrastichus setifer'' was used in
Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...
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 ( ) is a state in the New England region of the Northeastern United States. It borders Connecticut to its west; Massachusetts to its north and east; and the Atlantic Ocean to its south via Rhode Island Sound and Block Is ...
. In 2003, another parasitoid, '' Lemophagus errabundus'', was released in
Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...
and is now established in the region. Similar parasitoid releases have been made in
Boston Boston is the capital and most populous city in the Commonwealth (U.S. state), Commonwealth of Massachusetts in the United States. The city serves as the cultural and Financial centre, financial center of New England, a region of the Northeas ...
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