Control of weeds on small holdings should not be too difficult. Simply hoeing or pulling out the offending plants will often do. Some weeds such as perennial weeds may need more attention and persistent treatment.
It is important to be observant and to be willing to seek advice on the identity and control of plants you are not sure about. Often control is a simple matter depending largely on timeliness and prompt action.
Control methods available are:
- mechanical (handpulling, mowing, hoeing, cutting, cultivating, slashing)
- chemical (herbicide spraying, wiping)
- cultural (use of pastures, grazing, cropping and management)
- biological control (if available).
All methods can be effective depending on the weeds present and many other factors. Biological control has been effective only on certain weeds such as Skeleton Weed and Prickly Pear.
The use of herbicides is a popular method adopted by many people. Herbicides are easy to apply and use, but require much knowledge about their use and action on plants to obtain best results. They are possible sources of environmental contamination. However if used according to label directions they can be highly selective and very effective on most weeds.
There are legal requirements for the marketing and use of herbicides in New South Wales.
REMEMBER. READ THE LABEL AND USE ACCORDING TO THE DIRECTIONS ON THE LABEL.
Consult your local office of the Department of Agriculture for further information on the control of weeds by herbicides.
Submitting plants for identification:
Plants to be identified can be submitted to the Department of Agriculture. Specimens should first be taken to district advisory officers who may be able to identify the plant on the spot. Plants which are not readily identified are sent, by the officer, to the Royal Botanic Gardens in Sydney.
To aid in identification the following points should be noted.
- The specimen should be as complete as possible. If the plant is small, submit a complete specimen, with roots. Include samples of fruit, flowers and seed heads if possible, to assist identification.
- Submit the specimen as soon after collection as possible. If a delay is anticipated it is best to press the plant in dry newspaper. The newspaper should be changed daily to prevent mould developing.
- Supply as much information as possible to your district advisory officer on the habitat, density, flower and foliage colour of the plant.
Noxious Plants:
What is a noxious plant?
Noxious plants are weeds which are declared to be noxious by proclamation under the Local Government (Amendment) Act 1945. These weeds pose special problems to agricultural production and may affect human and animal health.
Legislation is not precise on what is meant by a noxious plant. Experience suggests that a weed should be considered for proclamation if it fits all the following criteria.
- The plant is likely to spread from its present site to other properties of average management where it is expected to cause serious harm or economic loss through its effects on man, domestic animals, crop, or pastures.
- There are reasonable and enforceable means available to kill the plant, to bring it under effective control, and to limit its spread.
- There is a firm intention to enforce control.
- A worthwhile benefit to the community is reasonably anticipated from enforced control with the methods available.
Responsibility for control:
Local Government councils are responsible for enforcing the control of noxious plants on council-owned land, privately owned land and on vacant Crown Land on behalf of the State government. All landholders and occupiers are required to take measures to control plants declared noxious on a State-wide or local government level.
The local council has a list of weeds declared noxious for its area. This list is usually published in local papers or can be obtained from shire or Department of Agriculture offices.
In addition to the noxious plants specific to each local government area, there are 21 weeds declared on a State-wide basis:
Parthenium
Indian hemp
Coca leaf
Opium poppy
Johnson grass
Columbus grass
Mesquite
Water lettuce
Nodding thistle
Spiny burr grass
Blackberry
Water hyacinth
Salvinia
Alligator weed
Lagarosiphon
Bathurst, noogoora, Californian
and cockle burrs
Serrated tussock
St John’s wort
Weeds officers:
Failure to comply with this notice will result in council either instituting legal proceedings for non-compliance or issuing a notice under Section 474 of the Local Government (Amendment) Act 1945, or both. Then council may enter onto the property and carry out the eradication work at the landholder’s expense.
The expense may be recovered by legal proceedings on the person to whom the notice was given. If the council cannot recover the costs of eradication from the occupier then it may recover the costs as a debt upon the land.
Who is an “occupier”?
“Occupier” in relation to land includes:
- any person holding any lease, agreement for or promise of a lease of land, or a licence or permit to occupy land
- any person in actual possession or occupation of land or entitled to be
- the occupier or caretaker of any public watering place
- the authorized agent of an occupier
- the resident manager or other person in charge of land upon which the occupier does not reside.
Responsibility of the occupier:
In the Act, it is very clear that all occupiers of private land shall take reasonable and effective measures to eradicate noxious plants from their land.
Prickly pears are not covered by the Local Government Act but come under the Prickly Pear Act 1924. The Prickly Pear Destruction Commission is responsible for enforcing the Act. Advice on all matters concerning noxious plant control is readily available from local councils and officers of the Department of Agriculture.
Identifying Plant Diseases:
Diseases of plants result from attack by parasitic organisms, for example fungi, bacteria, viruses, nematodes (eelworms), or from non-parasitic causes, for example heat, frost, and too much fertilizer.
Most councils employ a weeds officer whose duties include the inspection of private land for the presence of noxious plants. If noxious plants are found on a property the council will notify the landholder and recommend the method of control.
If on a further inspection the council is satisfied that reasonable and effective measures have not been taken, the council will issue a Section 473 notice (Form 2). This notice requires the landholder to eradicate (control) the noxious plants.
Plants suspected of being diseased can be submitted to the Department of Agriculture. Many diseases can be controlled, but the control measure to be adopted depends on the correct identification of the disease.
The Department of Agriculture can help you with disease identification and advice through the Plant Disease Advisory Service in the Biology Branch of the Biological and Chemical Research Institute, Rydalmere.
Specimens should be submitted in the first instance to district advisory officers. Your local agronomist or horticulturist may be able to identify the disease and give you advice on its control. To help in identification, particularly if the specimen has to be sent to Rydalmere from the local office, the following points are important.
- • The specimen should be as complete as possible. If the plant is small, a complete specimen, with roots, should be submitted. If large, such as trees, include samples of fruit, flowers and leaves and portions of twigs, bark and roots. Include plants that are severely affected as well as those showing early disease symptoms. The specimen submitted should be typical of the disease.
- If the identity of the plant is not known, include a specimen of healthy growth with flowers, fruit or both to make identification easier.
- Submit a fresh specimen as soon as possible after collection. Specimens collected in the field can be put implastic bags to keep them fresh.
- Submit 0.5 to 1 kg soil from around the roots with the specimen to enable tests to be made for unfavourable soil conditions or nematode attack. The soil should be moistened slightly and packed in a plastic bag.
- Give as much information as possible to your district advisory officer who has Plant Disease Report forms designed to include all relevant information.
- Submit specimens to the district advisory officer as soon as possible after collection. If a delay is anticipated they should be stored as described below.
Most leafy plants, woody wrap firmly in slightly damp plant parts and roots newspaper, then in several layers of dry newspaper. Succulent plants and wrap in dry newspaper, then plant parts pack round with dry material such as straw or crumpled newspaper.
Specimens of leaf diseases put between layers of dry (rusts, leaf spots) newspaper. Cereal and grass specimens wrap or press between dry newspaper.
Turf and pasture specimens collect as sods and pack firmly in a cardboard box.
- Generally if specimens are held in tightly closed tins or plastic containers for an undue length of time they will sweat and decay. The speed and efficiency of the service can be maintained if’ you follow these guidelines.
Plant Disease Control:
Fungicides and nematicides, registered under the Plant Diseases Act 1978, are available commercially in New South Wales for control of a number of fungal and nematode diseases of plants.
Although, in general, fungicides are not as toxic to humans as insecticides, they can be harmful if not used safely. The fumigant and non-fumigant nematicides are highly toxic to humans and some can only be used by licensed operators.
Safe use of fungicides and nematicides:
Despite some success in breeding resistance to disease, chemicals still play a major role in reducing the impact of diseases on the yield and quality of agricultural and horticultural crops.
Stringent conditions must be met before a product can be marketed for the control of diseases. The product must be approved by health and agricultural authorities. Its marketing and use in New South Wales is covered by legal requirements.
The importance of the safe, effective use of agricultural chemicals in disease control is continually stressed by the Department of Agriculture.
Safe, effective use means USE ACCORDING TO THE DIRECTIONS ON THE LABEL.
All the necessary information is written on the label and if the directions are followed, the user will not be endangered and harmful residues will not be found in food for human or animal consumption. It is particularly important to comply with the “withholding period” specified on the label which is the minimum time between the last application of the control measure and the use of the crop or pasture.
Protection of the environment should be of concern to all who use pesticides for pest and disease control. Bad publicity about pesticides is not warranted if they are used correctly. However, publicity emphasizes the need to avoid haphazard or indiscriminate use. Pesticides must be applied to specific pests and diseases on specific crops at the times and rates indicated on the label and in accordance with the withholding period and other directions on the label.
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