Serangan Tribolium castaneum pada Beras di Penyimpanan dan Pengaruhnya terhadap Serangan Cendawan dan Susut Bobot

Abstract

Tribolium castaneum is an important insect pest of stored milled rice in Indonesia. The effect of T. castaneum on fungal infection of stored milled rice was investigated together with moisture content and weight loss. Milled rice were placed in glass jars (250 g/jar) and infested with 5, 10, and 20 pairs of T. castaneum. As control, the jars contained only milled rice. Three replications were made for each treatment (including the control). The jars were stored in storage room for 1, 2, and 3 months. Moisture contents (based on wet weight) of milled rice were determined using the oven method. Fungi were isolated and enumerated using dilution plating, followed by pour plate method on Dichloran 18% Glycerol Agar (DG18). Weight loss (based on dry weight) was determined after 3 months of storage.The results showed, that the population of adult T. castaneum increased with the increase in the number of pairs of infested T. castaneum and storage duration. The moisture contents of milled rice were relatively constant during storage. It was assumed, that the moisture contents were more influenced by the environmental conditions rather than the occurrence of T. castaneum. Nineteen fungal species were isolated Aspergillus flavus and Penicillium citrinum were the dominant fungal species. Total fungal population decreased after 2 and 3 months of storage, with the increase in the number of pairs of infested T. castaneum. Weight loss increased with the increase in the number of pairs of infested T. castaneum. Based on weight loss of milled rice, the best storage duration was found when the number of pairs of T. castaneum was five pairs, the duration of storage was 1, 2 or 3 months of storage.