Biology
Stark and Goyer (1983) report the biology and behavior of
Neochetina eichhorniae in Louisiana. Adults lived an
average of 57.8 days in the laboratory. Adults averaged 2.8
eggs per night and laid eggs mostly at night on lower leaves
of the plants. Larvae hatch from eggs in about 8 days and
took 41 days to develop to pupae. Pupation occurs on the upper
part of the root system. There were four generations in southern
Louisiana. Larvae feed inside the leaf petioles. Adults prefer
to feed on the upper surface of the leaves, then lower leaf
surface and least preferred was the leaf petiole.
History
Neochetina eichhorniae was released into the United
States in 1972 along with N. bruchi and Sameodes
albiguttalis (Perkins 1973). It has been an important
insect for biological control of water hyacinth in many other
parts of the world.
Status
This weevil is the primary biological control agent for water
hyacinth. It is often found in conjunction with the chevroned
waterhyacinth weevil. Biological control programs with both
weevils are often more successful than with a single species.
Management
These weevils can be collected as adults on the plants. The
adults are active at night and can easily be collected up
on the foliage at that time. Adults can then be relocated
to new locations. Local populations of the weevil may need
supplemental releases of additional adults to enhance the
weevil population. Weevil populations are affected by cold
temperatures which may limit their use in some situations.
Adults are sometimes collected at lights.
Weeds Affected
Neochetina eichhorniae feeds on water
hyacinth.
Literature
Grodowitz, M. J., R. M. Stewart, and A. F. CoFrancesco. 1991.
Population Dynamics of Waterhyacinth and Biological Control
Agent Neochetina eichhorniae (Coleoptera: Curculionidae)
at a Southeast Texas Location. Environ. Entomol. 20(2): 652-660.
Perkins, B. D. 1973. Potential for waterhyacinth management
with biological agents. Proc. Tall Timbers Conf. Ecol. Anim.
Control Habitat Manage. 4: 53-64.
Stark, J. D., and R. A. Goyer. 1983. Life Cycle and Behavior
of Neochetina eichhorniae
Warner (Coleoptera: Curculionidae) in Louisiana: A Biological
Control Agent of Waterhyacinth. Environ. Entomol 12: 147-150.
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