Arable News

  • Written by: Farmers Guide
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Mites need controlling too

Poor storehygiene can lead to significant mite and pest attacks of stored grain, whichcan spoil quality, can be responsible for between 5% and 10% loss of yield oreven lead to complete rejection. With harvest not so far away and with controlmeasures starting up to one month before harvest, now is the time to plan whataction you are going to take. Growers need to maintain grain quality and yield instore so that they make as much profit as they can, even though prices are not asbuoyant as they have been, says Peter Waite of Dow AgroSciences.

In fact thispricing issue may mean small parcels of grain, kept to sell in May/June, arestill in store, ready to go when prices firm. Last years harvest was a goodone, so there was more grain to deal with than in the previous year, he pointsouts.

It is important to protect the investment made inthe crop so far when moving from field into store. Mite and pest infestationsresult in significant direct losses due to their feeding. Grain quality can beadversely affected, with problems of reduced nutritional value, taint andcontamination of insect fragments. The presence of mites can give rise to mouldinfestations as moisture and heat in the grain heap increases. Mites and pestsalso act as a source of allergens leading to difficulties when feeding animals,he says.

Peter remindsgrowers that various species of mites, weevils, beetles and moths are frequentproblems in grain stores and grain heaps.  Saw-toothed grain beetle and flour mites arethe most commonly occurring pest species in grain, yet some insecticides haveno effect on mites. Working by contact, ingestion and fumigant activity, theacaricide and insecticide Reldan 22 (based on chlorpyrifos-methyl) controls allmajor pests of stored grain. In fact it is the only pre-harvest grain storefabric treatment that controls the three main mite species flour mite, Cosmopolitanfood mite and Copra mite.

In addition itcontrols a long list of other insects – Saw-toothed beetle, Rust-red grainbeetle, Foreign grain beetle, Rust-red flour beetle, Confused flour beetle, Merchantgrain beetle, Indian meal moth, Warehouse moth, Mediterranean flour moth, Grainweevil and Rice weevil.

Reldan 22 is best used as part of an integratedmanagement approach to treat the fabric of the store. This process starts by completelyemptying stores of old grain or any debris. Any handling equipment such as airways, ducts, intake pits and elevatorsshould be swept or cleaned using a high pressure airline, paying attention tocracks and crevices where pests will harbour. The sweepings need to be disposedof well away from the grain store site or be burnt.

There are several application options for Reldan 22- by knapsack sprayer or by tractor-operated spray lance. The product isapplied at 200 mls in 5 litres of water per 100 square metres when treating thefabric of the store. It should be applied up to 4 weeks before harvest. Onetreatment is allowed. There is no withholding period.

It can also be used on harvested grain coming intostore as an admixture treatment. In this instance Reldan 22 is applied using asuitable applicator to grain that has been dried, cooled and cleaned. Afterthis admixture treatment, grain should not be processed for 90 days, so thisapproach is most suitable for grain intended for long term storage. Just oneapplication can be made per batch.

Peter Waite explainsthat Reldan 22 is approved for use on grain store structures and equipment aswell as on stored grain heaps of wheat, barley, oats, rye and triticale.  It is accepted by the British Beer and PubAssociation (BBPA) and the Brewing Research International (BRI) for use oncereals for malting and brewing.


  • Written by: Farmers Guide
  • Posted:
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