Cyrtobagous salviniae
Encyclopedia
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
(Salvinia molesta).
The adult weevil is about 2 millimeters long. It is brown in color during its first few days of adult life and soon turns shiny black. The female lays over 300 eggs one by one in the lower leaves and rhizome
s of the salvinia plant. The larva
is white in color and about 4 millimeters long. It burrows through rhizomes and feeds voraciously on new buds, warping and stunting the plant until it eventually sinks. The larva pupa
tes underwater amongst the rhizomes of the plants in a cocoon it weaves from root hairs
. Adults also damage the buds and leaves of the plant during feeding, but do less damage than the larvae.
This weevil is native to South America. It has been introduced to areas where giant salvinia is a problem. Early experimental successes occurred in parts of Africa and southeast Asia, and the weevil is now established in parts of Australia and the southeastern United States. In many cases the weevil has cleared salvina infestations by 90% or more in under one year. Entire waterways have been unclogged by the weevil's feeding. It also feeds upon Salvinia minima, a similar but less dramatic aquatic weed.
It is similar to the closely related Cyrtobagous singularis, but the two weevil species have slightly different ecologies and C. singularis is generally an ineffective substitute for C. salviniae.
Curculionidae
Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...
known as the salvinia weevil. It is used as an agent of biological pest control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
against the noxious aquatic plant
Aquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...
giant salvinia
Giant salvinia
Salvinia molesta, commonly known as giant salvinia or kariba weed after it infested a large portion of the reservoir of the same name, is an aquatic fern, native to south-eastern Brazil. It is a free floating plant that does not attach to the soil, but instead remains buoyant on the surface of a...
(Salvinia molesta).
The adult weevil is about 2 millimeters long. It is brown in color during its first few days of adult life and soon turns shiny black. The female lays over 300 eggs one by one in the lower leaves and rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s of the salvinia plant. The larva
Larva
A larva 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...
is white in color and about 4 millimeters long. It burrows through rhizomes and feeds voraciously on new buds, warping and stunting the plant until it eventually sinks. The larva pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
tes underwater amongst the rhizomes of the plants in a cocoon it weaves from root hairs
Trichome
Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.- Algal trichomes :...
. Adults also damage the buds and leaves of the plant during feeding, but do less damage than the larvae.
This weevil is native to South America. It has been introduced to areas where giant salvinia is a problem. Early experimental successes occurred in parts of Africa and southeast Asia, and the weevil is now established in parts of Australia and the southeastern United States. In many cases the weevil has cleared salvina infestations by 90% or more in under one year. Entire waterways have been unclogged by the weevil's feeding. It also feeds upon Salvinia minima, a similar but less dramatic aquatic weed.
It is similar to the closely related Cyrtobagous singularis, but the two weevil species have slightly different ecologies and C. singularis is generally an ineffective substitute for C. salviniae.