Grain Protectants Prevent Pests

Best Grain Storage Solutions

Grain protectants prevent pests

Grain protectants are one of many management tools for preventing pests in stored grain and have a particular role in unsealed storage and seed storage.

Key Points:

  • Consider using grain protectants when gas-tight sealable storage is not available and to ensure security of planting seed.
  • Grain protectants work best when combined with meticulous storage hygiene and aeration cooling.
  • Stringent maximum residue limits (MRLs) leave no margin for error in application. Always check with your grain buyer before applying.
  • Even coverage is required to reliably manage stored grain insects.

Growers across Australia’s northern and southern cropping regions can use grain protectants to help prevent pest infestations in stored grain. The use of protectants combined with meticulous hygiene and aeration cooling are especially useful in unsealed storages, where effective fumigation is not possible.

Grain protectants prevent pests

Pest prevention

Grain protectants are designed to prevent pest infestations and not to control existing infestations. Grain must be clean and free of pests before applying a protectant. A common misunderstanding is that grain protectants kill insects already infesting the grain, but those types of products (contact disinfestants) are no longer available for on-farm use.

In order to give protectants the best chance to defend stored grain, combine their use with meticulous storage hygiene practices before and after harvest. Cleaning up the storage site and the harvesting equipment removes harbours where pests can survive, ready to infest the new season’s grain. The addition of aeration cooling also provides an unattractive environment for pests in stored grain.

Read the label

Always read the chemical label before choosing a protectant to ensure it is registered for use on the grain you wish to apply it to and will target the main insects commonly found in your storage. As a general guide, most protectants are only registered for use on cereal grains, except malting barley, rice and maize.

The lesser grain borer (Rhyzopertha dominica) is the toughest of the common grain storage pests to deter with protectants, with only two products currently available – K-Obiol® and Conserve Plus. To prolong the working life of these two products, alternate their use each year or two to avoid pests developing resistance to them.

Close to MRL

As grain markets have become less tolerant to protectants and maximum residue limits (MRLs) are monitored scrupulously, accurate application is essential. Some of the protectants, even if used at the recommended label rate, are right on the MRL leaving no room for error in applying the correct rate and even spread. Commodity vendor declarations are also used in many cases to ensure a parcel of grain is only subjected to one application of the protectant to avoid exceeding the MRL.

Accurate application

Always follow label directions, but as an example some protectants are applied at a rate of one litre of mixed product per tonne of grain. To achieve even coating of the grain best results are achieved with one, or even better with two, flat fan nozzles mounted to spray into the auger as the grain is loaded into storage. Mixing 1 L/t is not easy and relies on agitation as the grain passes up the auger.

Applying protectants in a belt conveyor does not provide adequate mixing and even coating. Spray can also cause issues with the belt slipping on drive rollers. Some conveyor manufacturers offer a separate application kit — ensure it can apply the protectant evenly to the stream of grain and includes agitation to mix the product through the grain.

Some protectants start deteriorating 48 hours after being mixed with water so avoid leaving for long periods before applying to grain. The product label will also indicate the anticipated effective life of the protectant on the grain.

The effective life of protectants is shortened if applied to grain above 12 per cent moisture content (MC) and above 27°C or is exposed to direct sunlight, such as the end of a shed or an open bunker.


Conserve Plus

Conserve Plus is the latest addition to the Conserve family. Its formulation combines Spinosad and S-methoprene at 100 gm ai per L. Conserve Plus will be able to be used on all cereal grains, including malt barley. The first release will be the in a 500ml bottle that will treat 50 T grain. Conserve Plus will require a mixing partner to control rice weevil, and as such, Dow AgroSciences  released a 1L Reldan Grain Protector in Sept 2016 to partner Conserve Plus. When used on maize, the OP mixing partner is replaced with Fenitrothion 1000.

Conserve On-Farm

Conserve On-Farm is a grain protectant from DOW that has three active ingredients to control most major insect pests of stored grain, including the resistant lesser grain borer (LGB).
Conserve On-Farm provides six to nine months of control and has a nil withholding period (WHP). Maximum residue limits (MRLs) have been established with key trading partners and there are no meat residue bioaccumulation issues. Conserve On-Farm is a combination of two parts that are applied together. Using Part A and Part B together is very important to get control of the complete spectrum of insects.

Part A: 1 x 5 L of chlorpyrifos-methyl and S-methoprene – controls all stored grain insect pests other than the resistant lesser grain borer (Rhyzopertha dominica)

Part B: 2 x 1 L of spinosad – is very effective on the lesser grain borer, including resistant strains, but has little to no activity on other key species.

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