The principal causes of losses in quality and quantity of stored grains are rodents, insects,

and birds.

In Egypt, the estimated annual losses caused by rodents alone are about 4-10% in weight of stored grains, and the rate of damage to bags is between 10-26% (El-Lakwah,1984). Losses incurred in the shounas(open air storage) cannot be gauged from PBDAC's records since inventory control is exercised by counting of bags without regard to quality and quantity changes in their contents. A study performed during 1993/1994 aiming at determining losses in weight caused by pests as well as handling and transport for the stored wheat in shounas of the PBDAC in various governorates of Egypt reveals that losses vary generally from one shouna to another and are in range from 2-12.4% with a mean value of 6.5%. High loss values are obtained when wheat is heavily infested by Trogoderma granarium and heavy rodent attack. Results indicate also that the longer the storage period the higher the losses. Wheat storage period is between 4-8 months. Results concerning the losses caused by handling and transport reveal that quantities lost under the stack are from 8-46kgs/ stack with a mean value of 30.8 kgs. Quantities lost during transport have a mean value of 56.2 kg per stack. The calculated mean percentage of handling and transport losses is 0.21% of the total quantities of stored commodities. The total quantity of wheat loss in the various shounas of the PBDAC are 18769.6 tons during the storage period 1993/94, and its economic value is equivalent to 9.8 million Egyptian Pounds.(El-Lakwah and Laborious, 1995 under publication). The estimated losses at farmer's and merchant's level range from 4-10% for grains and pulses and equal to 20-50 million US Dollar annually (El-Lakwah, 1995 unpublished).

Kamel, (1977) mentioned that the estimated losses of stored products pests are about 3.7% of the annual production of cereal grains and 2.1% of main pulses (broad beans and lentils).

Results of investigations carried out during 1989/1991 in stores of the Kalyubia region showed that loss in weight of cereal grains is from 0.03-0.77% and for pulses 1.41-2.81% (El-Lakwah et al, 1993).