Through systematic and general investigation, 27 species of insect Pests and their naturalenemies were found in fodder. The
proportion of Coleoptera account for 63.9%. Thedominant species in material warehouse are Tribolium castaneum (Herbst.), Sitophiluszeamais (Motschusky), Rhyzopertha dominica (Fabricius), Palorus subdepressus(Wollaston). The dominant species in workshop are Alphitobius piceus Oliver, T. castaneum(Herbst.), S. zeamais (Motschusky). The dominant species in fodder are T. castaneum(Herbst.), R. dominica (Fabricius ), Cryptolestes minutes Oliver, P. subdepressus(Wollaston).The population density of the main insect pests peaks from June to September,
thepopulation quantity of the main dominant species changes discontinuously from season toseason. The order of the competition of initial
insect pest in fodder, from high to low, is R.dominica, S. zaeamais, and that of later insect pests is T. castaneum, Oryzaeyhilussurinamensis L., Cryptolestes ferrugineus (Steph). With the pellets of the fodder turningsmaller, the resistance to insect pests decreased. With plastic bags sealing for 261 days, thepopulation quantity of insect pests in fodder decreased 59. 7% than that of uncovered fodder.The resistant - insect bags can keep the fodder from being infested for two months.