Susceptibility of some cereal species and cultivars grown in Algeria to post-harvest damage by the rice weevil

Abstract

An experimental study was performed to assess the susceptibility to grain weevils of some cultivars of the major cereals produced in Algeria: durum, soft wheat and triticale. Two sets of grain samples of each variety were packaged and stored in comparable conditions for three months at 25 °C. One set was infested by Sitophilus oryzae and the second kept as a control. During storage, the insect population dynamics and major biochemical, nutritional and physical and chemical attributes were checked. Another experiment was performed only on varieties of durum in favorable conditions for rice weevil development. In the first study, durum was shown to be the least susceptible cereal species: weevils did not develop at moisture content below 12%. Triticale varieties were more susceptible to weevil damage than soft wheat varieties. After three months storage, the loss of weight for the most susceptible variety of triticale was ten times higher than for the least susceptible variety of soft wheat. The second experiment showed that not all durum varieties are equally susceptible to insect attack. A multivariate analysis, which related the main qualitative criteria changes to insect population density evolution with storage time, highlighted three variables influencing the major inter-varietal differences: storage time, moisture content and weevil population density. These results provide new data that can be exploited either in new cereal cultivar breeding or in elaborating Integrated Pest Management (IPM) strategies for cereal grain storage.