Where to obtain information
A wide range of publications, websites, apps and local landcare or land management experts can assist you with providing advice on a range of options before you take the first step on controlling pests, weeds or diseases on your property.
Get advice before loading the spray tank.
Weeds are probably the most common thing sprayed by small landholders. While the most popular control option for pests, weeds and diseases is often to use a spray, this is neither the only, nor always the best option.
If spraying is the best option, select a chemical that is registered for control of the pest, weed or disease you have correctly identified.
In addition to the information available through the Department of Primary Industries and Regional Development's Pest and Disease Information Service, there are some excellent commercial databases available such as Infopest.
In the public domain, the Australian Pesticides and Veterinary Medicines Authority (APVMA) has a comprehensive database of all currently registered products and permits, which enables you to view or download product labels.
A less comprehensive database which also brings up the labels and material safety data sheets (MSDS), is Pestgenie.
Read the label
After selecting a suitable product, read and follow the label directions. This is a legal requirement. Most people only look up how much to mix.
Just as important is the timing. Weeds need to be controlled when they are small and actively growing. It is near impossible to kill mature weeds, irrespective of how much spray you use.
It is also a waste of time and herbicide to attempt to kill weeds when they are under stress because the weather is too hot, too cold or too dry. The weed shuts down in these conditions and the herbicide is not taken up by the plant.
Similarly, insects need to be sprayed when they are small and there are not too many of them. Caterpillars larger than 8mm are just as hard to kill as big weeds. If the bugs arrive in numbers, you will experience severe damage and losses before the spray takes effect.
Like weeds and insects, plant pathogens have to be detected early and a spray applied before the number of spores increase dramatically.
Check the label to see:
- if an adjuvant has to be added to the spray mix
- what spray equipment can be used
- how to mix the pesticide in the tank
- if there is a minimum water volume recommended
- what personal protective equipment (PPE) to wear to protect your health
- when crops or pastures can be harvested or fed to livestock after spraying (the withholding period (WHP))
- what environmental precautions need to observed – like not spraying when bees are foraging.
Always check the label to determine how water quality may affect a particular chemical. Some chemicals can be rendered inactive by poor water quality.
Ensure you have your water tested and are aware of any quality issues — wetter and adjuvants are available to ameliorate quality issues if necessary.
Select your weapon
For spot spraying, (spraying individual weeds) a knapsack sprayer is adequate. However, if you need to spray woody weeds or vines, such as blackberries or lantana, a powered wand is required. A knapsack is incapable of putting out the volumes necessary to wet big blackberry bushes, for example.
Small boom sprays mounted on ATVs or tractor three-point-linkages (3PL) usually have the option of a hand gun running off the pump.
To spray weeds spread throughout a pasture, the usual equipment is:
- a small boom spray mounted on the back of an ATV
- tanks attached to the front and/or rear carry racks
- a small diaphragm pump running off the battery or a small 3PL boom on a utility tractor
- the pump powered by the tractor’s power take-off (PTO).
It is common for this equipment to include a hand wand for woody weeds and spot spraying. If it is an option, it is worth choosing for the added versatility it provides. Weed wipers are another alternative that can be used to stop weed seed set in crops or pastures.
There area a range of different types of weed wipers including rotary, blanket, wick and rope wipers.
Made to measure
Calibration involves measuring how much spray the sprayer puts out. Labels usually include two mixing rates: a dilution rate, for example, 100mL chemical per 1L water or an area rate, for example, 2L/ha of chemical in a minimum water volume of 50L/ha.
Dilution rates are only suitable for spot spraying. Rather than mix up and spray away, it is useful to know how much spray you are putting out, so you can avoid both over or under-application.
Over-application wastes pesticide and puts excess pesticide into the environment. Under-application generally results in a spray failure.
To calibrate a boom spray, you need to know how much each nozzle puts out, the swathe or spray width of the boom, and the speed of the sprayer. When you have these three figures, it is then a matter of putting them into the formula.
Nozzle output is measured using a measuring jug and stopwatch or tip tester. The swathe is the sum of the width of the boom plus one nozzle spacing.
Sprayer speed needs to be checked by timing the sprayer across 100m, rather than relying on the speedometer.
The correct nozzle needs to be selected to give the droplet spectrum required by the target, and to deliver the required output.
More and more labels specify droplet spectrum, for example, medium to coarse, and most labels will recommend an output or flow rate, for example, 50L/ha. Nozzles can be selected by looking up nozzle charts. These charts are available in hard copy, and also on the web.
You can learn more about calibration in pesticide training courses and calibration sheets are available. Training courses will also teach you how to read and use nozzle charts.
Be trained, be safe
In Australia, training is required when using certain categories of pesticides. Even if it is not mandatory for you to be trained, it is in your best interests to undertake training.
Training will ensure you can read and apply labels, calibrate and use your spray equipment effectively and safely and know your legal obligations when spraying.
To find a suitable course and location refer to the AusChemWA website.
Be responsible
Contact your local authorities to find out whether or not you have to be trained. Even if you don’t have to be trained, you are still subject to the legislation in your state that controls use of pesticides.
For example, you may have to keep records, and you will certainly be responsible for any pesticide that drifts off your property and harms someone else, be they a neighbour or a sensitive environment.
Ensure you dispose of used chemical containers responsibly. DrumMuster is the national program for the collection and recycling of empty, cleaned, non-returnable chemical containers.
Also make sure you wear personal protective equipment (PPE) to help keep you safe when spraying.
PPE equipment can include:
- overalls/water proof pants and jacket
- gloves
- water proof boots
- safety glasses/face shield
- breathing apparatus
- hat.
Before spraying any chemicals on your property it is important to get advice on the right type, application and safety gear required.