The objective of this study was to evaluate the economic loss level (ELL) for the main insect-pest of stored wheat - Sitophilus zeamais (Motschulsky, 1895). In order to achieve this, the level of infestation was related to qualitative and quantitative losses after three months of storage. Glass containers (2.5 L) were filled with 1.5 kg wheat (type "durum"; harvested in Sept., 1997) with 12.5% moisture content. The wheat was infested with 0, 2, 10, 20, 30, 50, 100, 200, and 300 individuals of S. zeamais, in three replications. The glass containers containing infested wheat were stored for 90 days in BOD chambers at 27 ºC and 65 ± 5% relative humidity. After the storage period, the grain temperature was measured and the number of live and dead insects was counted. Grain weight loss and quality (moisture content and "bulk density") were analyzed. The final mass and the bulk density were corrected for the initial moisture content. The market value of national and imported wheat, the cost of fumigation as well as the regression coeficients between grain weight and quality losses, and insect infestation were used to estimate the ELL. Based on the grain weight loss, bulk density, and the market value of wheat, the ELL was 0.18 insects kg-1 of grain.
stored wheat; qualitative loss; infestation of insects
