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Pest Control and Treatment
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Insecticides
One of the most popular control methods is to spray bulk grain with an insecticide as it is relatively cheap and little further attention to the grain is needed. Consumers have recently shown an increased resistance to the residues of insecticides on food, with the result that this method has become less popular. Insecticides that are used for this purpose must be selected very carefully so as not to have any negative consequences for the consumer.
Store Grain Dry
Another way of controlling pests is to store grain as dry as possible. The prescribed maximum moisture levels may not be exceeded. Remember that insects produce more rapidly if the grain contains more water. When the moisture content exceeds 15%, fungal spores start to develop, and fungi destroy the grain even faster than insects.
Creating a Non-Conducive Atmosphere for Insects
The atmosphere can also be made unfit for insect life in three ways:
- By applying poisonous gas (fumigation).
- By reducing the oxygen concentration by exchanging it with carbon dioxide or nitrogen gas (controlled atmosphere technique).
- By a combination of poisonous gas application and the reduction of oxygen.
In all three cases the altered conditions must be maintained for a certain minimum period, which varies from 1-16 days. It also requires a certain minimum gas-tight standard of the storage space. If the storage structure is sufficiently gas-tight, the altered atmosphere can be maintained for the full storage time, which eliminates the need for repeat treatments. For the application of the controlled atmosphere techniques and in some types of fumigation, an appropriate gas circulation system is needed to distribute the gas evenly through the grain.
The rate at which insects develop, depends directly on the environmental temperature. Development occurs more rapidly between 16-37°C, depending on the species. The temperature at which development occurs the quickest is called the optimum temperature for that species. Fir every species there is also a minimum temperature below which development will come to a halt. This temperature varies from 7°C for grain mites up to 24°C for the khapra beetle.