PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
LEGISLATION
contd
Obtain a summary
of local weed
legislation
which will have current
lists of declared weed
species and your
responsibilities
Councils often
have designated
Weeds Officers
CULTURAL
METHODS
A seed bank
is supplemented
by incoming weed
seeds transported
via wind, etc.
It is important to
regulate seed
populations
Grow Me
Instead
Programs
.
STATE/TERRITORY/REGIONAL/LOCAL COUNCIL LEGISLATION
Noxious weed legislation exists in all States/Territories and varies slightly
from state to state and between local council areas. Noxious weeds are grouped into
classes which can vary from a few to many, depending on the state/territory.
However, in all cases the legislation aims to reduce the negative impact of
significant weeds on the economy, community and environment, by establishing
control measures to prevent the introduction and establishment of new weeds,
restricting the spread of existing weeds and eradicating specified weeds. Control
measures are prescribed by legislation and depend on the weed in question. The
Australian Weeds Committee prepares and updates the ‘Noxious Weed Lists for
Australian States and Territories. Individual weeds, State and Territory lists or the
entire noxious weed list (in table form) can be accessed via the following website:
Weeds in Australia www.weeds.gov.au/
– ‘Prohibited’ weeds pose a serious threat and have potential to spread, notification
of their presence is required; they may need to be continually suppressed, contained
or eradicated and it is illegal to keep, sell or move them.
– ‘Restricted’ weeds have potential to spread, trade in these weeds and materials
containing them is prohibited.
– Eradication of pest plants from the state or parts of the state may be required.
– Contain, suppress, and control certain weeds in only parts of the state/territory.
– Weeds not to be introduced into the state/territory.
– Penalties. Control of noxious weeds is legally the responsibility of the private
landholder, local authority (councils etc) or State/Territory government
– Others, eg compulsory control of certain weeds on public or government land.
Specific Acts/Tree orders/Taskforces, etc
– Various taskforces have been set up, eg NSW Lantana Taskforce, Prickly Pear Act.
– Seed Acts make it illegal to sell grain, fodder or crop seed which contains seeds or
any other parts of a noxious weed capable of growing.
– Quarantine legislation.
– Tree Preservation Orders may conflict with weed legislation. If a 40 meter tall
‘protected’ tree is found to be an environmental weed, how do you prevent seeding.
Many voluntary schemes, eg Weed Swaps for less invasive species. Spencer
(2006) suggested ‘retro-fitting’ gardens, eg a property could be certified weed-free,
issued with a voucher to purchase alternative plants from the nearest garden centre.
States/Territories/Shires/Councils have weed information on their websites.
An Exotic Weeds Watch List is available online.
CROP COMPETITION.
Many crops compete strongly with weeds when established but need protection during
their early growth. Some crops, eg onions which germinate and grow slowly, have narrow
erect leaves and wide row spacings, compete poorly with weeds.
Control weeds prior to planting, eg tillage, herbicides, slashing, greenmanuring,
grazing.
Increase and maintain ‘crop’ vigor to compete effectively with weeds
during germination, establishment and maintenance, to reduce the need for weed
control and reduce flowering and seed set on surviving weeds.
– Cultivar selection, smothering out weed competition early.
Select varieties adapted to site, soil, water availability and season.
Select perennial pasture species to reduce weed establishment and assist in
reducing existing weed infestations.
Choose wheat varieties with leafy and strong early growth.
Trees dominate site and shade out weeds. Mass plantings or dense prostrate
species control weeds by early canopy closure, crowding and shading. Useful
for rockeries and general plantings between trees and shrubs, vegetable gardens.
Crops can be genetically engineered to more effectively compete with weeds,
resulting in increased production and reduced need for herbicides (page 436).
Legume pasture can substantially reduce a ryegrass seedbank.
– Sowing dates should coincide with optimum soil temperature, moisture, etc for
the crop, to encourage rapid establishment and growth. Fertilisers are more
efficient when weeds are controlled at planting.
– Sow at rates so that crops rapidly occupy all space above and below ground.
Narrow row spacing with high sowing rates can quickly shade areas between
plants in some cases.
Control pests and diseases, gaps and weakened plants can reduce yields and
provide space for weeds to grow.
Replacement vegetation. Accompany weed removal with a planting program,
eg planting a crop, re-vegetation of bush areas by seed or tube stock, replacing
invasive plants with safer alternatives. Local councils have lists of alternatives
suitable for their regions. NGIA is expanding the Grow Me Instead program.
432 Weeds - Integrated Weed Management