''Larinus curtus'' is a species of

true weevil The Curculionidae are a family of weevils, commonly called snout beetles or true weevils. They are one of the largest animal families with 6,800 genera and 83,000 species described worldwide. They are the sister group to the family Brentidae ...

known as the yellow starthistle flower weevil. It is native to Southern Italy, Southern Europe, the Middle East and

the Caucasus The Caucasus () or Caucasia (), is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, incl ...

. It is used as an agent of

biological pest control Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or ot ...

against the

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or lives ...

yellow starthistle (''Centaurea solstitialis'') in the United States. The adult weevil is dark brown or black with light colored mottled hairs on its body. It is about long. The female lays glossy, milky white, oval-shaped eggs at the bases of open yellow starthistle flowers. The

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 ...

emerges from its egg in a few days and goes inside the

flower head A pseudanthium (; : pseudanthia) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers ...

, where it feeds on the developing seeds. A larva is capable of destroying all of the seeds inside a given head, with an average reduction of 96%. The adult feeds on flowers and pollen but probably does little damage to the plant. It is the larva's impact on seed production that helps control the plant's spread. There have been field reports of large numbers of adult ''L. curtis'' feeding on safflower flowers ''

Carthamus tinctorius Safflower (''Carthamus tinctorius'') is a highly branched, herbaceous, thistle-like annual plant in the family Asteraceae. It is one of the world's oldest crops; today, it is commercially cultivated for vegetable oil extracted from the seeds. ...

'', but no evidence that larvae have successfully developed on this plant. This weevil is native to southern Europe and the Mediterranean. It was first introduced to the United States as a biocontrol agent in 1992. It is now established throughout the

Pacific Northwest The Pacific Northwest (PNW; ) is a geographic region in Western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though no official boundary exists, the most common ...

, but in relatively low densities.

References

* Coombs, E. M., et al., Eds. (2004). ''Biological Control of Invasive Plants in the United States''. Corvallis: Oregon State University Press, 429.

External links

USACE Biocontrol Profile
* https://web.archive.org/web/20150923195902/http://www.cal-ipc.org/symposia/archive/pdf/2007/4.1biocontrol-smith.pdf Lixinae Insects used for control of invasive plants Biological pest control beetles {{Curculionidae-stub