Determining of clear and hidden infestation of stored cereals and beans with insect pest in warehouses

Aims: The survey of storage pest while entry and maintenance in the warehouse is of special importance in pest control. The aim of this study was to determine the obvious and hidden contamination of stored cereals and beans with insect pests in the warehouses of Tehran. Methods: This descriptive cross-sectional study was carried out in 2010 in the central warehouses of Tehran province. Sampling of cereals and beans was performed according to the method of Standards Institute and Industrial Research of Iran. Products' waste percentage was determined by calculating and weighing the damaged seeds per 100 grams of sample. Results: Overall, the mean contamination of cereals was 0.005 ( ±0.001) grams per 100 grams regardless of the sampling time and the product type. The highest and lowest rate of contamination was respectively observed in split pea and wax bean. Obvious live pests were observed in lentil, split pea and red bean and hidden pests were seen in rice and lentil. Among the identified live insect pests Callosobruchus maculates and Oryzaephilus surinomensis were more abundant, respectively. Conclusion: The rate of contamination of cereals and beans in the warehouses of the two studied units is less than the permitted limit and products have the needed quality. The warehouse management system is desirable for controlling pests and preventing their growth, but the isolation of hidden pests shows that the screening methods of products on entry time are inappropriate.