Technical highlights - Department of Primary Industries ...

21. Ecology and control of wet tropics weeds
Project dates
January 1999 – June 2013
Project leader
Melissa Setter
Tropical Weeds Research Centre
Tel: (07) 4064 1149
Email: melissa.setter@deedi.qld.gov.au
Other staff in 2010–11
Stephen Setter, Katie Patane, Wayne
Vogler, Laura Roden and Barbara
Madigan
Objective
Increase our understanding of the
ecology and control options of key
wet tropics weeds to improve their
management.
Rationale
Weeds pose a major threat to the high
economic, environmental and social
values of land in the wet tropics. Many
wet tropics weeds are relatively recent
arrivals and have not reached the
full extent of their range and impact.
Much of the basic ecological knowledge
required to develop comprehensive
long-term control strategies for wet
tropics weeds is unavailable. This
project conducts field, shadehouse and
laboratory experiments on a number
of priority weed species. Research
findings will enable land managers to
more effectively limit weed impacts on
natural ecosystems, primary industries
and tourism.
Methods
Field, shadehouse and laboratory
experiments are currently underway
on a number of weed species, including
pond apple (Annona glabra), navua sedge
(Cyperus aromaticus) and bog moss
(Mayaca fluviatilis).
Pond apple mechanical control
Mechanical control of pond apple may
be a viable option in some areas during
drier periods. We test two different
machines—the Positrack and the
Tracksaw—for their kill rate, amount
of follow-up control required, costeffectiveness
and selectivity (effect on
native vegetation). Trials are performed
in pond apple infestations of similar size
and density at the Daintree (Positrack)
and in Innisfail (Tracksaw). There are
notable differences between the two
machines: the Positrack creates mulch
from the destroyed plants, while the
Tracksaw has herbicide application
integrated into its control method and
thus requires only a single operator. (For
the Positrack experiment, we applied
herbicide by hand.)
Navua sedge
We conduct a foliar herbicide screening
trial near Millaa Millaa on the Atherton
Tableland and we use the results to
determine the next phase of herbicide
trials. The aim is to develop effective
selective herbicide options for navua
sedge control in sown tropical pastures
and non-agricultural areas.
Bog moss
We undertake field trials in a small
drain infested with bog moss to provide
control options for this emerging
aquatic weed. Treatments include the
use of herbicides (UniMaz 250 4 L ha –1
with Bonus wetter 1.5 L ha –1 ) as well
as shadecloth (92% light reduction)
and black plastic (for more sensitive
environments).
We also conduct a herbicide screening trial
in the glasshouse, in which 10 herbicides
(triclopyr, endothal, glyphosate, imazapyr,
metsulfuron, dichlobenil, flumioxazin,
bispyribac, carfentrazone and diquat
+ guar gum) are added at two rates to
submerged bog moss growing in 2 L jars.
The most effective herbicides are then
tested in a rates trial in jars and in a large
container trial with emergent bog moss.
Progress in 2010–11
Pond apple mechanical control
We have established transects and
applied the mechanical control
treatments; monitoring and analysis are
ongoing (Table 21.1). Very wet conditions
prevented access, so we could not control
regrowth as planned. Fruiting has been
observed on resuckering trees 18 months
after treatment.
Photo 21.1 Stephen Setter applying herbicides to a navua sedge plot as part of initial
screening trials
Part 2 Landscape protection and restoration 45