Technical highlights - Department of Primary Industries ...

16. Biological control of mikania vine (Mikania micrantha) in Papua New Guinea and Fiji
Project dates
July 2006 – June 2012
Project leader
Michael Day
Ecosciences Precinct
Tel: (07) 3255 4453
Email: michael.day@deedi.qld.gov.au
Objectives
Introduce and establish biocontrol agents
for mikania vine in Fiji and Papua New
Guinea to:
• reduce the impact of the weed to
small-block holders and plantation
owners in areas where it is a problem
• reduce the seed load and thus the
possibility of further spread into
northern Australia
• establish successful biocontrol
methods for use in northern Australia
if required
• promote biocontrol as a safe and
successful weed-control method
• train scientists in Fiji and Papua New
Guinea in biocontrol methods.
Rationale
Mikania vine (Mikania micrantha) is
native to tropical America and is now
a major weed throughout the South
Pacific and South-East Asia. The
plant is a perennial vine that grows
extremely rapidly, about 1 m month –1 ,
smothering crops and plantation trees.
In Queensland, mikania vine is currently
confined to the wet tropics region, where
it has the potential to significantly affect
the sugar, horticultural, beef and tourist
industries and to spread throughout
northern Australia. Mikania vine is a
Class 1 declared weed in Queensland
and is the target of a national cost-share
eradication program. Biological control
of mikania vine in the South Pacific was
first attempted in the 1970s. However,
the agent failed to establish. This project
aims to introduce two butterfly species
(Actinote anteas and A. thalia pyrrha)
from Indonesia and the mikania rust
(Puccinia spegazzinii) into both Fiji and
Papua New Guinea.
Better control of the weed in
neighbouring countries such as Papua
New Guinea and Fiji will in turn
reduce the risk of further spread into
Queensland. A greater understanding of
mikania vine and its biocontrol agents
will also boost the state’s capacity
to respond to an incursion if the
eradication program is unsuccessful.
Methods
Suitable agents are selected based on
results of host-specificity testing and
field observations in other countries.
We send information on the agents’
life histories and host ranges to our
collaborators in Fiji and Papua New
Guinea, and request import permits.
For the mikania butterflies (A. anteas
and A. thalia pyrrha), additional host
testing will be conducted in Fiji prior
to field release. For the mikania rust
(P. spegazzinii), CABI Europe–UK
conducts additional host testing. We
submit reports on the host testing of the
agents to quarantine authorities in Fiji
and Papua New Guinea. On approval,
suitable agents are reared for release in
both countries.
We field-release agents throughout areas
of Fiji and Papua New Guinea where
mikania vine is a problem. Provincial
staff assist in the release of agents as part
of their training in biocontrol activities.
We also set up programs for monitoring
plant density and spread as well as for
agent establishment, population increase,
spread and impact on mikania vine.
Progress in 2010–11
Mass-rearing and field-release of
P. spegazzinii in both Fiji and Papua
New Guinea continued throughout
2010–11. In Papua New Guinea, the
rust was released at nearly 300 sites in
12 provinces in which the presence of
mikania vine is confirmed. Pustules
have now persisted on field plants at
more than 120 sites in 10 provinces and
some pustules have been found more
than 30 km from the point of release
after 12 months. It is still too early,
or the sites are too distant, to confirm
establishment at many of the other sites.
Field monitoring of several release sites
around the research station at Kerevat
found that the rust is having a severe
impact on mikania vine. At one plot the
rust suppressed the growth of mikania
vine, which allowed other plants to smother
the plant, reducing its cover substantially.
Photo 16.1 Jenitha Fidelis from the Cocoa and Coconut Research Institute, Papua New Guinea,
showing rust-infected mikania to villagers in East New Britain Province, Papua New Guinea
Part 2 Landscape protection and restoration 35