Noxious Weeds
Weeds
A weed is any plant growing where it is not wanted. Most plants we think of as weeds have particular characteristics that make them undesirable.
Some weeds are declared noxious by legislation and must be contained or controlled. These weeds are known as noxious weeds and are controlled by the Noxious Weeds Act 1993 in NSW. For more information about noxious weeds click here. For information on the Athel pine (a variant of noxious weed) click here.
Problems that weeds cause include:
- reduced crop yields through competition for light, moisture and nutirents
- contamination of harvested produce, eg weed seeds and burrs in wheat
- reduced productivity of pasture
- livestock poisoning
- tainted milk, meat and flour
- physical damage to animals, eg hides and eyes
- human health problems, eg allergies
- interference with human recreational actvivity
- blockage of irrigation channels, drains, lakes and dams by aquatic weeds
- weeds in wilderness and park lands that cause environmental problems
- weeds in industrial areas that can cause environemtnal problems
- weeds that harbour other pests and host insects, diseases, feral animals, etc
Weed types may be
- narrow leaf (monocotyledons) eg grasses
- broad leaf (dicotyledons) eg thistles, capeweed etc
Life cycles may be
- annual (grow and die in one year)
- perennial (grow over many years)
- biennial (grow and die in two years)
Weeds may spread by:
- wind
- water
- animals/birds
- machinery
- contaminated seed/stock feeds/fodder
- man
Every effort must be made to prevent weeds spreading from infested areas to clean areas. Weeds invade a new area if it favours them more than the plants already there, or if there is some disturbance of the vegetation which allows the invading weeds to become established. The weeds you can see in an area tell a story about what has happened in the past and how the place is now being managed. Weed problems may change over time and control of weeds is a long term problem.
