Grain and Grain Products Pests

(granary pests), creatures that injure or destroy grain and grain products during storage and shipment. Dried fruits and vegetables and medicinal, leather, tobacco, and other raw materials also suffer from pests.

Grain and grain products pests include arachnids (certain mites), insects (certain beetles and butterflies), birds (certain pigeonlike and passeriformes), and mammals (mouselike rodents). There are over 100 species of grain and grain products pests. The most dangerous in the USSR are the flour, long, and common hairy mites; grain weevil, rice weevil, yellow mealworm beetle, confused flour beetle, saw-toothed grain beetle, rufous grain beetle (Laemophloeus testaceus), bread beetle, lesser grain borer, white-marked spider beetle, cadelle (Tenebroides mauritanicus), pea weevil, dried-bean weevil, lentil weevil, other weevils, corn moth, Angoumois grain moth, and Mediterranean flour moth; common pigeons and house sparrows; and rats, mice, and voles.

Grain and grain products pests are universal, and they do great damage. According to data of the UN Food and Agriculture Organization, every year insect pests alone destroy at least 5-10 percent of the world’s grain supplies. Some species live only in closed places (grain weevils, pyralids), others in granaries and in the field (rice and dried-bean weevils, among others), and still others winter in granaries (pea, lentil, and other weevil species). These pests reduce the germinating power of seeds, contaminate grain and grain products and decrease their weight, diminish the nutritional and bread-baking qualities of grain, promote the self-warming of wet grain, transmit the spores of stinking smut (grain weevils), and carry the potato bacillus (mites). Rats and mice eat large quantities of grain, contaminate grain stores, damage buildings, equipment, and containers, and spread plague, cholera, tularemia, anthrax, and other diseases among human beings and domestic animals. Birds eat grain and contaminate it.

Grain and grain products pests are controlled by prevention and extermination (by physical-mechanical and chemical methods). The principal preventive measures include preparing, cleaning, and disinfecting of storehouses, processing plants, land, machines, gear, and warehouse implements; observance of sanitary-hygienic rules for storing grain and grain products; the chilling of grain in cold weather to 10° C or lower; and cleaning and disinfecting of parts of fields to be used for stacking and threshing grain. Extermination can be accomplished by physical-mechanical methods and by chemical methods.

Physical-mechanical methods include cleaning contaminated grain and groats in grain cleaners, as well as sifting flour and sometimes groats. The walls and floor of a compartment and the surfaces of machines, gear, and closed bags are cleaned with brushes or vacuum cleaners. Passive and active chilling of grain and grain products is common. Contaminated grain with a high moisture content is dried in grain driers under the maximum possible temperature conditions. Active ventilation devices are also widely used for chilling and drying. Disinfestation of grain by ionizing radiation is considered a promising method. Chemical methods include wet, aerosol, and gas disinfestation of compartments; gas disinfestation of grain and grain products; and the dusting of seed grain with powdered preparations. KZMB [concentrated emulsion of 80 percent green oil], polychlorpinene, thiophos, chlorophos, trichloromethaphos-3, DDVF, and other products are used for wet disinfestation of empty compartments. Technical hexachloran in green, diesel, or solar oil, and insecticidal cartridges are used for aerosol disinfestation (using generators). Chloropicrin, dichloroethane, and methyl bromide are used for gas disinfestation; calcium and sodium cyanide mixture and discoid cyanide-impregnated absorbents of prussic acid are used to treat milling, groats, and combined feed plants. Grain is gassed with dichloroethane (seed), chloropicrin and methyl bromide (food, forage, and seed peas), and methallylchloride (food and seed). Special measures are employed to fight rodents. To protect grain and grain products from birds, screening is put onto windows, trapdoors, doors, and ventilation pipes; bird nests in granaries are destroyed in the spring and fall.

Methods to combat grain and grain products pests are carried out in combination with measures for individual, group, and antifire safety.