Identification, preference and potential damage of dominant stored product insect pests on several noodle products of Monde Nissin Corporation [Terminal Report]

The life cycle, feeding preference and infestation behavior of three stored product pests namely: red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), rice weevil complex, Sitophilus spp. (Coleoptera: Curculionidae) and rice moth, Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) in four Monde Nissin Corporation (MNC) products and milled rice were evaluated in the laboratory. The offspring of both the red flour beetle and rice weevil complex were unable to develop into adults in all the MNC noodle variants indicating that these pests will not develop and multiply on said noodle products. In contrast, 18.75 to 28.95% of the rice moth larvae initially introduced in the MNC variants emerged into adults but emergence was significantly prolonged from 100-123 days. Although the MNC variants were not suitable for development of the rice moth, still this pest might pose a problem in the storage of MNC products. In contrast, very high number of rice weevil offspring emerged on milled rice while moderately number of offspring developed with the introduction of red flour beetle. Likewise, 96% of the first instar larvae of rice moth larvae emerged into adults in rice bran with the first adult emergence recorded at about 33 days after insect introduction. The ability of the storage pests to enter into the packaging materials at three and five months of storage while exposed to relatively high pest population in a confined plastic container was evaluated. Despite high population of the red flour beetle and rice weevil complex, these pests were unable to enter the packaging materials even at five months of storage. On the other hand, the number of holes caused by rice moth larvae on the packaging materials and the number of larvae inside the packaging materials were negligible in all the MNC products at three moths of storage. An abrupt increase in the number of rice moth larvae and holes was recorded at five months storage with heavy damage on the noodles of all the MNC products. The feeding preference of red flour beetle and rice weevil complex on the different MNC products was not evident and both pests were unable to develop into adults. Among the MNC products, significantly higher number of rice moth eggs were oviposited in MNC Product C than the other MNC products. However, the total number of emerging moths in the different MNC products (41 to 55.75 adults) did not significantly differ among the products. Results of the study showed that the red flour beetle and the rice weevil complex may pose very minimal damage on the different MNC products since these pests were unable to reproduce and to develop in these products. Although the MNC products were not suitable for the development of rice moth, exposure of products to high population of rice moth larvae beyond three months of storage resulted to damage on packaging materials and caused severe damage on the different noodle variants.