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?