Growers urged to check expiry dates on stored chemical

image of Gordan Cumming
Grains Research and Development Corporation Manager Chemical Regulation Gordon Cumming is encouraging growers to check stored chemicals for date of manufacture and any expiry dates. Photo GRDC.

With improved seasonal conditions and an upbeat spring forecast, grain growers across New South Wales and Queensland will be carefully assessing the need for disease management over coming months and taking steps to ensure they have adequate fungicide supplies on hand.

For some this has meant purchasing extra fungicide to avoid the costly problem of running short while others will take the opportunity to utilise chemical that has been stored over the past couple of years due to the drought.

In both instances, storing chemicals appropriately and checking the expiry date on labels can maximise safety, storage stability and ultimately efficacy according to Grains Research and Development Corporation (GRDC) Manager Chemical Regulation Gordon Cumming.

“As most growers are aware, it’s important to adhere to the ChemCert requirements for the safe storage of chemical,” Mr Cumming said.

“These include ensuring stored chemicals aren’t exposed to extreme heat and UV; are kept out of direct sunlight and in a well ventilated area; are correctly segregated (such as into flammable and non-flammable); stored on robust shelving in an area that is lockable; and having the relevant personal protective equipment, first aid, fire extinguishers and Material Safety Data Sheets on-hand.

“At the same time, growers need to be mindful of a chemical’s date of manufacture and if there is an expiry date for any specific products which will be stated on the label.

“In some cases, chemicals may expire two years from the date of manufacture which could have implications for using previously stored products or holding product over for next year.”

Agricultural chemical products can undergo chemical and physical changes during storage and how quickly this happens depends on the nature of the active constituent/s, the non-active components, formulation type, packaging and, particularly the storage conditions such as temperature, light and humidity.

In many instances, the product remains fit for use as long as these changes don’t adversely affect application, biological performance, operator safety, consumers or the environment.

For example, chemicals formulated as suspension concentrates can settle out over the course of time. But provided care is taken to fully resuspend the product prior to addition to the spray tank, these can be used effectively so long as they have been stored appropriately.

Under Australian Pesticides and Veterinary Medicines Authority (APVMA) legislation, most agricultural chemical products are not date-controlled (that is, there is only a date of manufacture on the label with no expiry date) and should remain within specification for at least two years when stored in its unopened, original container, away from direct sunlight at normal room temperatures.

However the APVMA legislation also states that products containing certain active constituents are date-controlled and have approved shelf lives as per the expiry date on the label. These active constituents include the fungicide mancozeb as well as some insecticides such as dimethoate.

Mr Cumming encouraged growers to check the date of manufacture on all products and ensure that the oldest product is used first.

He said specific note should be made of products that include an expiry date on the label next to the date of manufacture.

“Products that have passed their expiry date should not be used as their physical characteristics may have changed and this can lead to blockages within spray equipment during application,” Mr Cumming said.

“This may increase operator exposure due to the need to clean spray equipment during operation.

“Even if the product looks fine the activity or efficacy of the product cannot be guaranteed if it has expired. We all know that the most expensive spray job is the one that does not work.”

If in doubt, growers should contact their local product supplier for advice on shelf life.

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