''Euhrychiopsis lecontei'' is a type of

weevil Weevils are beetles belonging to the Taxonomic rank, superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and Herbivore, herbivorous. Approximately 97,000 species of weevils are known. They b ...

that has been investigated as a potential

biocontrol 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 ...

agent for Eurasian water milfoil. It is found in the eastern and central

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

and western

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 ...

Life cycle

''E. lecontei'' is a

holometabolous Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the superorder Endopterygot ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

, undergoing true

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

. Development is temperature dependent, but the time to develop from egg to larvae is about 4 days, from larvae to pupae 13 days, and from pupae to adult 13 days. Larvae are stem borers and damage plant tissue from about 7 cm from the tip of the plant.

Use as a Biocontrol

Milfoil weevils occur in natural populations in much of North America on their native host, Northern watermilfoil (

Myriophyllum sibiricum ''Myriophyllum sibiricum'' is a species of water milfoil known by the common names shortspike watermilfoil, northern watermilfoil, and Siberian water-milfoil. It is native to Russia, China, and much of North America, where it grows in aquatic hab ...

). They often reach sufficient densities to suppress invasive Eurasian watermilfoil (

Myriophyllum spicatum ''Myriophyllum spicatum'' (Eurasian watermilfoil or spiked water-milfoil) is native to Europe, Asia, and north Africa, but has a wide geographic and climatic distribution among some 57 countries, extending from northern Canada to South Africa. It ...

) infestations after a prolonged infestation or artificial augmentation. Studies indicate that for effective control a density of about 1 weevil per two stems of milfoil (0.5 weevils per stem) is necessary. There are mixed reviews that fish such as

bluegill The bluegill (''Lepomis macrochirus''), sometimes referred to as "bream", "brim", "sunny", or "copper nose" as is common in Texas, is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and ...

s can reduce weevil populations as research has only been conducted in very limited settings. Augmenting native weevil populations as a biological control is effective as long as there is a small amount of milfoil to sustain the population. Milfoil weevils are commercially available as a management option for Eurasian water milfoil by a firm based in the United States and Canada.

References

{{DEFAULTSORT:Euhrychiopsis Lecontei Baridinae Beetles of North America Beetles described in 1896