Study On The Effect Of Sitophilus Oryzae Linnaeus And Rhyzopertha Dominica Fabricius On Cereal Quality Indicators

In this paper, we studied variations of the bored kernel percentage (BKP) and thousandkernel weight(TKW), damage terizations, moisture and gluten water absorption when wheatwere infected by different densities adults of Sitophilus oryzae (L.) and Rhizopertha dominica(F.) in20weeks. Comparative study of the changes in these indicators were excuted, toexplore the relationship between the degree of insect infestation and changes of grain qualityindicators change. The main findings are as follows:The BKP were increased while the TKW were reduced when wheat were infected by adultsof oryzae (L.) and dominica (F.) with time increasing.When Rhizopertha dominica (F.)infected wheat at the population density of4and6adults per kilogram of grain the BKP wereless than6.0%and10.0%after14weeks and16weeks.The changing threshold were14weeks and16weeks. And that for what infected with the population density of10adults were10weeks and16weeks. Sitophilus oryzae (L.) infected wheat in the population density of4and6adults per kilogram of grain the BKP were less than6.0%and10.0%after14weeks and18weeks.The changing threshold were14weeks and18weeks. And that for wheat infectedwith the population density of10adults were10weeks and16weeks. BKP had verysignificantly positively correlation with pest density and storage time while TKW had verysignificant negative correlation with pest density and storage time.There were some hazards when wheat infected by pest and different kinds of pest leftdifferent hazards. Wheat surface covered with white flour when wheat infected byRhizopertha dominica (F.),and the hazards phenomenon was very obvious. While wheatsurface covered with gray flour when wheat infected by Sitophilus oryzae (L.),and the hazardsphenomenon was not obvious. Damage characterizations had a closer relationship with thepest species than pest density.Moisture of wheat decreased slightly during the storage time. Pest activity could elevatedthe wheat moisture, and difference of wheat it after Rhizopertha dominica (F.) and Sitophilusoryzae (L.) infected wheat was slight. Moisture had very significantly positively correlationwith pest density and storage time.When wheat gluten water absorption decreased during storage, quality deteriorationoccured, the pest activities led to deterioration of acceleration. When wheat was infected with pests at Sitophilus oryzae (L.) had more negative effect on wheat. When they were infectingwheat in the population density of4and6adults, the two pest infected wheat gluten waterabsorption was less than180%after12weeks, and the threshold that cereal quality changefrom well to not very good was12weeks. The infecting wheat in the population density of10adults, wheat gluten water absorption threshold was12weeks and wheat gluten waterabsorption threshold was in8weeks. Gluten water absorption had very significantlypositively correlation with pest density and storage time.