What are the factors that can enhance insect infestation in stored grain?

Stored grain in storage structures were spoiled due to attack of different insects-pests, fungi, rats, mice, squirrel, birds etc. In storage, a number of biotic and abiotic factors and their interactions are responsible for insect multiplication and subsequent grain damage.

The occurrence and development of an insect infestation is dependent on many factors such as source of insects, available food, temperature, moisture, air, condition of the feed-stuff, presence of other organisms, and the efforts to exclude or kill the pests.

Major factors responsible for enhancement of insect damage are: temperature, relative humidity, and moisture content of the feed ingredient.

Temperature is the most important environmental factor affecting insect development and reproduction. Most insects do not reproduce at temperatures lower than 12 °C or higher than 34 °C. The optimum temperature for reproduction is about 26 °C.

The nutritive content and certain physical properties of feeds will also determine the vulnerability of such materials to attack. Only a few insect species are able to attack sound kernels of feed grains.

Different insects and spoiled grain provide suitable conditions for growth of fungi and further spoiled the grain. Primary pest that cause most grain damage are the granary, rice and maize weevils; the lesser grain borer; and the Angoumois grain moth.

High moisture content (16 percent or more) renders feed grains soft and susceptible to attack. High grain moisture content due to prevailing high atmospheric humidity generally above the safe moisture levels (14% for paddy, 13% for milled rice, 12% for wheat, 1% for oilseeds and 9% for pulses). Meals pressed into cakes or hard flakes are more resistant. Insects appear to eat small particles more readily than large ones.
What are the factors that can enhance insect infestation in stored grain?

Storage of grain: Factors to be considered

Storage of grain: Factors to be considered
Storage facilities vary from small inexpensive steel or wooden bins on the farm, to elaborate incorporating mechanized ventilation.

On the farms, the circular type of steel bin holding approximately 1,000 bushels of grain is popular, while for terminal storage, a single elevator often has a capacity of several million bushels.

Virtually all of large storage and central market elevators, as well as many country elevators, are built of reinforced concrete so as to attain many years of usefulness and to reduce the fire hazard.

Marketing wheat commercially depends upon the concept that, when reasonable dry, the grain can be stored for long periods without undergoing a change in grade.

Deterioration of wheat in storage with a consequent lowering of grade can have serious economic consequences for the elevator operator.

Wheat is a biological material which is alive and it can deteriorate and die in storage of either the moisture content or temperature becomes too high.

Wheat is also subject to attack by microorganisms, insects and rodent when storage conditions are inadequate. For safe storage the following must be considered

*Moisture content
*Temperature of the wheat
*Infestation
*Type of bin

Storage deterioration can be controlled by drying damp wheat to safe moisture content and keeping it dry and cool, by providing good storage structure, and by aeration or forced ventilation.

Fumigation or chemical protectants will control infestation.

There is ample evidence that, under optimal conditions, wheat does not deteriorate with storage space age, at least for several years.

It appears that the length of storage of wheat within reasonable limits, has no appreciable influence on the storage properties of the flour milled from the wheat.

When wheat is stored improperly, deterioration is possible from many causes including:

*Insect damage
*Molds
*Heat damage
*Damage to the germ
*Sprouting
*Rotting
*Damage by rodents

These factors not only injure wheat and cause economic loss by lowering its value for milling or other end uses, but they can also cause actual loss in weight of the wheat, bring about undesirable changes in odor, sanitary quality, and nutritive value, and can alter important properties of starch, lipids and protein.
Storage of grain: Factors to be considered