Grain protectants are most effective when grain is treated into clean facilities. The following steps will help ensure grain storages begin and remain insect-free for the storage duration. For more information, view the "Best practice Application Guide" video in the link below:
If you are unable to view the video, follow this
Know the key pests
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Remove insect food sources and control the base insect population – good hygiene is critical to reducing the overall potential insect burden.
Clean up old bags and points of insect harbourage.
Clean up old grain residues that accumulate in and around storages.
Remove all dust and grain residues before applying a structural treatment.
Ensure out-loading augers and aeration ducts are clean.
Accurate calibration is essential to ensure the correct dose is applied evenly to the grain consignment. Calibration simply involves adjusting grain and protectant flow rates until the correct application rate is reached. Constant grain flow is vital to ensure correct and even application of chemical. Always keep the auger choke fully covered and avoid dispensing chemical into augers that are not full of grain.
Measure the time taken for your auger to deliver a known quantity of grain at a set angle into the silo. Then calculate the amount of liquid protectant that is needed to treat this much grain. If the angle of operation varies significantly with different silo heights, this can affect +/- auger output, and would require the commodity to be re-calibrated to this new angle of operation.
Measure the amount of liquid that is actually being delivered over the same time and adjust the flow rate until the correct rate is reached. It is important to ONLY use water when calibrating equipment to avoid exceeding pesticide MRLs to the test commodity.
Application rate of liquid
Conserve On-Farm (after dilution) is used at 1 L of mixture per tonne of grain. The following quick calculations will help to calibrate your spray:
multiply mL/min at nozzles by 0.06 to give required auger throughput in t/hr e.g. 1000 mL/ min * 0.06 = 60 t/hr.
multiply t/hr at auger by 16.67 to give the required spray delivery in mL/min. e.g. 60 t/hr * 16.67 = 1000 mL/min.
It is important to calibrate your equipment every time you spray, allowing for different grain flow rates.
Make up only the amount of diluted Conserve On-Farm required for the current job. If the operation is interrupted (e.g. by bad weather or machinery breakdown etc.) the dilute mix may be stored for 48 hours, as long as it is kept away from sunlight and agitated thoroughly every 8 hours.
Prepare the grain protectant spray application and augering systems.
Ensure grain protectant products are on hand.
Calibrate spray application equipment and augers prior to harvest.
Position the spray nozzle so as to allow suitable coverage and mixing as the auger lifts the grain up into the storage.
Position the spray nozzle to allow maintenance and calibration checks.
The position of the spray line nozzle can vary on the equipment, determined primarily on the auger barrel length. If the nozzle is too close to the hopper on longer augers, it can create too much drag and affect elevator output. The nozzle must be positioned to allow suitable coverage and mixing as the flyting lifts the grain up and into the storage. The nozzle location must allow ease of access to check for spray pattern and nozzle blockages which can occur in the presence of grain dust.
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Apply the grain protectant ensuring all grain is protected
Effective application of grain protectants relies on the even distribution of a very small amount of pesticide through the entire grain mass. Uneven distribution may leave pockets or layers of unprotected grain and insect infestation is inevitable.
Note: The use of stream nozzles or the practice of tipping the protectant mixture irregularly into the hopper are ineffective.
Most on-farm grain protectants are applied to the grain while it is being augered into storage, allowing the auger to do most of the mixing.
Once the grain protectant has been applied
Record the details of the grain protectant application
In most states, it is a legal requirement to keep a detailed record of all pesticide applications – when applied, with what product and rate to what commodity. This record will aid the completion of the Commodity Vendor Declaration when the commodity is sold and out turned.
Clean the application and elevation equipment after use
An important step in the application process is cleaning out the application and elevation equipment, once the application is completed. If other grains such as PRF cereals, canola or pulses are to be stored or elevated using the same equipment, these may pick up unwanted traces of protectants or other pesticides applied as they are elevated or transferred.
Manipulate the storage environmental to limit or prevent insect reproduction
Cool and dry environments are least favourable for storage pest insects. The table below outlines the importance of manipulating the grain storage environment.
Aerate the grain
Aeration is an important tool to reduce grain temperature, helping to reduce pest numbers and maintaining grain quality. Aerators should be switched on when filling the silo once ducts have been covered. An automatic controller will provide the most reliable results. Aim for a grain temperature of 20°C in summer and less than 15°C in winter.
Reduce the grain moisture
Grain moistures above 12% combined with 30°C temperatures provide conditions which favour insect breeding. Higher grain moisture in storage significantly increases the risk of moulds or mycotoxins forming on some commodities. The stockfeed processing sector places a strong focus on checking cereal grains at delivery to detect mycotoxins or moulds. These can have a serious animal health impact in processed feeds.
Monitor the storage
Stored grain should be inspected at least once a month. Take a grain sample from the silo base, and if safe, from the top grain peak. A bucket, insect sieve, sticky tape, magnifying glass, pest identification photos and a grain probe are all valuable tools for inspecting grain. When sampling, smell the grain and look at the grain surface for any signs of insect or moisture damage. If storage pests are found, keep a sample and identify them. Seek advice and take appropriate action (e.g. fumigation in a gas-tight storage.)
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