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Stored grain after harvest, whether stored in the national grain depot or farmers home, if improperly stored, will be affected by stored grain pests. Some farmers have suffered serious losses due to the infestation of stored grain pests, with nearly 300 pests per kilogram of wheat and a weight loss of 10% or more.

The biology of storage pests is to constantly crawl around in the grain pile. Is there a way to control stored food pests without the use of synthetic chemical pesticides that have environmental and human health impacts? Yes, it is diatomite, a natural insecticide used to store grain pests. Diatomite is a geological deposit formed from the fossilized skeletons of numerous Marine and freshwater single-celled organisms, especially diatoms and algae. These deposits are at least two million years old. Diatomite powder of good quality can be obtained by digging, crushing and grinding. As a natural insecticide, diatomite powder has good absorbability and has broad application prospect in controlling stored grain pests. Diatomite is rich in natural resources, non-toxic, odorless and easy to use. Therefore, it is advocated that it should be used in rural areas to create a new way for pest control of stored grain in rural areas. In addition to good absorption capacity, the particle size, uniformity, shape, pH value, dosage form and purity of diatomite are important factors affecting its insecticidal effect. Diatomite with good insecticidal effect must be pure amorphous silicon with particle diameter &lt. 10μm(micron),pH < 8.5, contains only a small amount of clay and less than 1% crystalline silicon.

Various factors affecting diatomite powder to control stored grain pests were studied in the United States: dosage form, dose, test insect species, contact mode between pests and diatomite, contact time, grain variety, grain state (whole grain, broken grain, powder), temperature and water content of grain, etc. The results showed that diatomite could be used in the integrated management of stored grain pests.

Why diatomite can kill stored grain pests?

 This is because diatomite powder has a strong ability to absorb esters. The body of a grain – storing pest has a rough surface and many bristles. The diatomite powder rubs against the body surface of the stored grain pest as it crawls through the treated grain. The outermost layer of the insect’s body wall is called the epidermis. In the epidermis there is a thin layer of wax, and outside the wax layer there is a thin layer of wax containing esters. Although the wax layer and the protective wax layer are very thin, they play a very important role in keeping the water inside the insect body, which is the “water barrier” of the insect. In other words, the “water barrier” can keep the water inside the insect body from evaporating and make it survive. Diatomite powder can powerfully absorb esters and waxes, destroying the “water barrier” of pests, making them lose water, lose weight and eventually die.