MANAGING GRAIN IN STORAGE

HOW GRAIN BECOMES INFESTED Grain may become infested in a number of ways. In many grain-growing regions. infestation starts in the field before the crops are harvested. This is. Of course, particularly true in the South. where the rice weevil and other insects are abundant in the field at harvesttime, and in the soft red winter wheat region of the Eastern States, where the Angoumois grain moth is often extremely destructive. In the more northern States that experience severe winters. Field infestation is negligible. In addition to field infestation. which may he important (depending on the region or the season). there are several othersources of infestation of stored grain that are of considerable importance. In all regions, it is customary to store grain year after year in the same bins. If these bins are made of wood, cracks and crevices become filled with grain dust and broken grain and afford places of concealment for many insects. Insects such as the cadelle burrow into the wooden sides or floors to pupate and later emerge in enormous numbers. Grain bins are not always properly cleaned; hence, fresh grain stored in them quickly becomes infested. Storing bran, shorts, and other milled feeds in or near the granary is another cause of infestation, since these products are invariably infested. Many bins, too, are located in barns that normally contain products in which insects breed. Temporary storage of grain in country or crib elevators frequently adds to the danger of infestation. Such storage is difficult to keep free from infestation, and clean grain often becomes contaminated by infested grain brought to the same place. Grain may also become infested while moving it in railroad boxcars to terminal elevators. Many grain-infesting insects live in the grain dust and waste grain that accumulate in cracks of the floors or woodwork and in the linings of the boxcars. Storage of clean grain in ware-houses and elevators that already contain infested grain also results in contamination through the movement of insects from the infested grain to the clean grain. Before shipment, uninfested grain should not be placed in sacks previously used for grain storage because these old sacks often harbor insects, as shown in figure 21, unless they have been sterilized by heat or fumigation. Certain extensive and costly infestations have been traced directly to the use of secondhand, infested, untreated grain sacks. Grain stored in open or poorly constructed cribs or bins may become infested by insects flying in from the outside. HOW TO PREVENT OR REDUCE PRIMARY INFESTATION Adoption of the combine harvester has reduced field infestation of small grain to a negligible amount. To prevent infestation after harvest, it is recommended that producers take the following steps: (1) Store only dry grain in weather-tight, rodent-proof bins, preferably made of steel; (2) clean out all bins before loading with grain; (3) spray the walls and floors of wooden bins and around the door frames of metal bins; (4) clean up and dispose of litter, waste grain, and feed accumulations in and around farm buildings; (5) apply protective powder, or spray, directly to grain as it is binned, or fumigate promptly after binning; and (6) inspect the bins monthly and fumigate if an infestation is discovered. In the North Central States, exposure to winter weather in most years kills off infestations in ear corn stored on the farm; hence, the loss from insect attack is not significant if the corn is to be used for feed during the ensuing season. Following mild winters, the Angoumois grain moth may he destructive, so under such conditions. it is well to shell corn in May and store it in tight bins. In the Southern States, field infestation can he reduced by: (1) Growing corn varieties with tight shucks those are semi-resistant to field infestation; (2) disposing of infested grain in farm storages before the corn reaches the silking stage; (3) early harvesting; (4) applying a protectant; (5) drying and shelling; and (6) storing the corn in tight bins suitable for fumigation. Information regarding the prevention or reduction of grain infestation is contained in other publications of the Department of Agriculture. SOURCE https://www.ams.usda.gov/sites/default/files/media/StoredGrainInsectsReference2017.pdf