Larinus planus | |
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Species: | L. planus |
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Larinus planus (Fabricius, 1792) | |
Larinus planus is an insect of the Curculionidae ("true" weevil) family. They are oval shaped, dark brown or black, and about 5–10 millimetres (3⁄16–3⁄8 in) long. [1] While native to Europe, it is also common in North America. It feeds on floral buds, primarily of thistles, with the larvae stage being the most destructive to them. In North America, it has been used as a biocontrol agent. [2] It is also known as Larinus carlinae. [3] [4]
The adult weevil is mostly dark brown or black, but has red-brown antennae. It is about 5–10 millimetres (3⁄16–3⁄8 in) long and oval shaped. The wing covers have light colored mottled hairs on them and appear pock-marked. The nose is long and narrow, with a pronounced curvature. [5] [6]
The eggs are black and appear the size of a "pin-prick." Once hatched, the larva has a segmented white body with a brown head, and is C-shaped. [1]
This weevil is indigenous to southwest England, as well as Central and Eastern Europe. [5] [1]
It was accidentally introduced to Canada and the United States in the 1960s. The first published record is from Maryland in 1971. [7] It is now widespread throughout North America.
Adults emerge in the spring, and begin feeding on thistle buds. They require buds ranging in size from 5-7mm. The insects mate when the temperature is at least 22 °C (72 °F), which is usually about 14-16 days after they emerge. The female deposits a single egg in each floral bud, and then seals it. After hatching, the larva feeds on the floral bud it is hatched in. In doing so, it destroys about 95% of the seed contents. Another brood of adults emerges in late Autumn. These adults spend the winter in plant litter, to emerge in the spring. [1]
Larinus planus prefers dryer ranges, but can also adapt to wetter locations. It does well in sunny areas with well drained soils. [1]
In Canada, it has been used as an agent of biological pest control against the noxious weed Canada thistle (Cirsium arvense). It was subsequently evaluated in the United States as a biocontrol agent and distributed across a range of the Great Plains in the western United States. [8] [9]
In 2000, it was found feeding on Cirsium undulatum var. tracyi, a sparsely distributed thistle native to western Colorado and eastern Utah. Subsequent research determined that the weevil reduced seed production of the native thistle. [9] It has also been found to have an adverse effect on the native and threatened Cirsium pitcheri . [10]
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 other natural mechanisms, but typically also involves an active human management role. It can be an important component of integrated pest management (IPM) programs.
Onopordum acanthium is a flowering plant in the family Asteraceae. It is native to Europe and Western Asia from the Iberian Peninsula east to Kazakhstan, and north to central Scandinavia, and widely naturalised elsewhere, with especially large populations present in the United States and Australia. It is a vigorous biennial plant with coarse, spiny leaves and conspicuous spiny-winged stems.
Cirsium arvense is a perennial species of flowering plant in the family Asteraceae, native throughout Europe and western Asia, northern Africa and widely introduced elsewhere. The standard English name in its native area is creeping thistle. It is also commonly known as Canada thistle and field thistle.
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 places. It is also known as golden starthistle, yellow cockspur and St. Barnaby's thistle.
Exapion fuscirostre is a species of straight-snouted weevil known by the general common name Scotch broom seed weevil. It is used as an agent of biological pest control against the noxious weed known as Scotch broom.
Cyrtobagous salviniae is a species of weevil known as the salvinia weevil. It is used as an agent of biological pest control against the noxious aquatic plant giant salvinia.
Cyphocleonus achates is a species of true weevil known as the knapweed root weevil. It is native to southern Europe and the Mediterranean and is used as an agent of biological pest control against noxious knapweeds, especially spotted knapweed. It has recently been spotted in India.
Larinus minutus is a species of true weevil known as the lesser knapweed flower weevil. It is used as an agent of biological pest control against noxious knapweeds, especially diffuse knapweed and spotted knapweed.
Larinus obtusus is a species of true weevil known as the blunt knapweed flower weevil. It is used as an agent of biological pest control against noxious knapweeds, especially spotted knapweed.
Larinus is a genus of true weevils, comprising about 180 species, mostly in the Palaearctic region with some species introduced to North America. Turkey appears to have a significant diversity of the group, with more than 50 species recorded in the eastern part of the country.
Phrydiuchus tau is a species of true weevils known as the Mediterranean sage root weevil. It is used as an agent of biological pest control against noxious weed Mediterranean sage.
Rhinocyllus conicus is a species of true weevil. It is best known as a controversial agent of biological pest control which has been used against noxious thistles in the genera Carduus, Cirsium, Onopordum, and Silybum.
Eustenopus villosus is a species of true weevil known as the yellow starthistle hairy weevil. It is used as an agent of biological pest control against the noxious weed yellow starthistle.
Larinus curtus is a species of true weevil 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 against the noxious weed yellow starthistle in the United States.
Cirsium undulatum is a species of thistle known by the common names wavyleaf thistle and gray thistle. It is native to much of central and western North America from British Columbia east to Manitoba and south as far as the State of Durango in Mexico. It has also been found outside of its native range as an introduced species.
Trichosirocalus horridus is a species of true weevil, native to Europe. It is a biological pest control agent that was introduced into the United States in 1974 to control exotic thistles, especially in the Cirsium and Carduus genera.
Cirsium perplexans is a species of flowering plant in the family Asteraceae known by the common names Rocky Mountain thistle and Adobe Hills thistle. It is endemic to Colorado in the United States, where it occurs in the Colorado and Gunnison River Valleys in the Rocky Mountains.
Larinus turbinatus is a species of true weevil in the family of beetles known as Curculionidae.
Larinus sturnus is a species of cylindrical weevils belonging to the family Curculionidae, subfamily Lixinae.