Biological Control
Of Invasive Plants
Information Retrieval System
|
|
Biological Control |
| University of Florida | Aquatic, Wetland and Invasive Plant Information Retrieval System |
Water hyacinth was introduced
from South America into the US in 1884. Since then it has spread into
many
lakes and
rivers of the southern US, making it one of the most troublesome aquatic plants in the
country.
The first biocontrol insect
released against water hyacinth in US was the mottled water hyacinth
weevil
(Neochetina eichhorniae). Its life cycle is 90 to 120 days, depending on temperature
and other factors; both the adults and the larvae feed on various parts of the plant. This weevil
was first released in Florida in 1972, and subsequently in several other states. It also has been
established in Australia, Fiji, Honduras, India, Malaysia, Papua New Guinea, South Africa,
Thailand and has been released in several other countries.
The second biocontrol insect released against water hyacinth in the US was another Neochetina species: the chevroned water hyacinth weevil (Neochetina bruchi), first released in Florida in 1974. Its life cycle is shorter than that of N. eichhorniae; its impact is similar.
Another biological control insect introduced against water hyacinth is the Argentine water hyacinth moth (Sameodes albiguttalis). Its life cycle is only 30 days; the larvae are the only life state that feeds on the plant. It was released and is established in Florida, Louisiana and Mississippi, as well as in Australia, South Africa and Sudan. It may retard growth in the early stages of water hyacinth mat development.
Not all biocontrol insects are from somewhere else. The larval stage of Bellura densa (formerly Arzama densa), a native southern US moth commonly known as pickerelweed borer, also attacks water hyacinth. Efforts were made in the early 1980s to augment natural populations of the moth's larvae in an effort to cause an impact on water hyacinth plants in Louisiana. There was little impact.
