|
Mimosa was introduced to Australia from tropical America
in the late 1800s as a curiosity. People were fascinated by
the fact that when the leaves were touched, they folded up.
But the plant escaped from the Royal Darwin Botanic Gardens
and entered the Adelaide River system.
It now forms impenetrable thickets over more than 800 km2
of the Northern Territory and is a threat to Kakadu National
Park and other wetland areas in tropical Australia and Asia
and has invaded Queensland. Where it blankets the landscape,
it reduces biodiversity, competes with pastures and hinders
access to water.
Background
Twelve insect species and two fungal pathogen species have
been released in Australia over the last 22 years and are
now having noticeable impact on this recalcitrant weed. Seven
of these insects are well established and abundant. They are
the flower-feeding weevil Coelocephalapion pigrae, the twig
and stem-mining moths Neurostrota gunniella and Carmenta
mimosa, the seed-feeding beetle Acanthoscelides puniceus,
the leaf feeding beetles Chlamisus mimosae and Malacorhinus
irregularis and the looper moth Macaria pallidata.
The reduction in plant growth and seed production caused
by the biocontrol agents has allowed other vegetation to compete
with mimosa resulting in the retreating of the edges of many
mimosa stands. With the current suite of agents, widespread
mimosa control may still be decades away so biological control
must be integrated with other control options. The research
has shown that the biological
control agents prefer the edges of stands so integration
of these with other control methods which break up the stands
could increase the effect of these agents. Herbicides and
fire could be used to break up the stands into smaller patches
of plants thus exposing more plants to insect attack. Biocontrol
agents were also more abundant on regrowth after the use of
these other methods.
Several new agents are being investigated that damage the
roots and leaf buds, parts that still lack effective agents.
The Project
Biocontrol - Biological control provides the most
promise for controlling mimosa as chemical and physical control
are expensive and, on land that is often flooded for months,
access can be next to impossible.
Integrated weed management
Ecological research
Key People
Tim Heard
CSIRO Entomology
Long Pocket Laboratories
120 Meiers Road
Indooroopilly QLD 4068
AUSTRALIA
Ph: +61 7 3214 2843
Fax: +61 7 3214 2885
Email: tim.heard@csiro.au
Collaborators
Northern Territory Department
of Primary Industry and Fisheries
Publications
Research and Management of Mimosa pigra (2004) Julien,
M; Flanagan, G; Heard, T; Hennecke, B; Paynter, Q; and Wilson,
C. (Editors) CSIRO Entomology, Canberra, Australia.
|
