''Larinus curtus'' is a species of

true weevil True most commonly refers to truth, the state of being in congruence with fact or reality. True may also refer to: Places * True, West Virginia, an unincorporated community in the United States * True, Wisconsin, a town in the United States * Tr ...

known as the yellow starthistle flower weevil. It is native to Southern Italy, Southern Europe, the Middle East and the Caucasuses. It is used as an agent of

biological pest control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...

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 injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...

yellow starthistle ''Centaurea solstitialis'', the yellow star-thistle, is a species of thorny plant in the genus ''Centaurea'', which is part of the family Asteraceae. A winter annual, it is native to the Mediterranean Basin region and invasive in many other ...

(''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 (; 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 ...

emerges from its egg in a few days and goes inside the flower head, 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 commercially cultivated for vegetable oil extracted from the seeds and was used by the early Spanish colonies along ...

'', 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 (sometimes Cascadia, or simply abbreviated as 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 ...

, 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