With significant investments having been made to maximize yields in the field, growers should not risk any yield loss post-harvest with poor grain store hygiene. Now is the time to plan and action the preventative action that you are going to take, says Vaughn Stansfield of Dow AgroSciences.Vaughn reminds growers that grain mites, weevils and beetles are frequent problems in grain heaps and grain stores and can be responsible for up to 10% of yield loss. “A 10% yield loss on a 10 tonne crop of feed wheat is worth £168 - a lot of money these days. In addition to direct losses due to feeding of mites and pests, grain quality can be adversely affected, with problems of reduced nutritional value, taint and contamination of insect fragments. The presence of mites can also give rise to opportunistic mould infestation as a consequence of increased heat in the grain heap. Grain is a precious commodity and needs comprehensive protection from any losses in store,” he says.“Nowadays there is a more limited choice of insecticides for treating the fabric and structure of grain stores. The approval of Actellic 50 EC (pirimiphos-methyl) for use as a structural treatment has been revoked. Other products aren’t recommended for all cereals, such as milling wheat, whilst other products don’t control mites, which are major and very common pests in grain that you can’t ignore.”Working by contact, ingestion and fumigant activity, Reldan 22 controls all major pests of stored grain, including mites, weevils, beetles and moths. “In particular it is the only pre-harvest grain store treatment that controls the three main mite species – Acarus, Lepidoglyphus and Tyrophagus,” says Vaughn.Grain store fabric treatment should be used as part of an integrated management approach. Up to one month before filling, grain stores need to be emptied of any old grain or debris. The store and any grain handling equipment including airways, ducts, intake pits and elevators should be swept or cleaned using a high pressure air line, paying close attention to cracks and crevices where pests can harbour. The sweepings should be disposed of well away from the grain store site or ideally be burnt. Any grain handling equipment should also be cleaned thoroughly.“Then you are ready to spray all the structural surfaces of the empty store and handling machinery, taking care to treat all cracks, crevices and joints. There are several options for application, by knapsack sprayer with fan spray nozzles, by motorised knapsack sprayer or tractor-operated spray lance."