| Popis: |
Fish is an important source of protein, mineral salts, and fatty acids essential for human nutrition. To ensure permanent availability to feed a hungry population, this very highly perishable commodity is transformed and stored. However, during storage, the dry fish suffer significant quantitative and qualitative losses due to insect pests. To characterize the damage of these pests, a study was conducted at the laboratory on two species of smoked and dried fish (Cyprinus carpio Linnaeus,1758 and Clarias gariepinus Burchell, 1822) free from any chemical treatment, and infested by three species of ichthyophagous insects (Dermestes frischii Kugelann 1792, Dermestes maculatus De Geer 1774, and Necrobia rufipes De Geer 1775). For this purpose, 100g of dried fish were introduced into a jar to scarce each of the three pests. Three replications were made and observed for 90 days in the laboratory. The weekly follow-up of the damage is made, and the kinetics of the losses are observed and snapped. Weight losses are accessed; in addition, emerging insects were extracted, identified, and counted. It appears from these investigations that the genus Dermestes is the most noxious to all dried fishes. After 90 days of storage, D. frischii causes a loss of 50.57% of the fish, D. maculatus 53.42%, and N. rufipes 31.57% of weight losses. The emergence of adults does not differ significantly for all fishes. The weight loss index on smoked fish shows that D. frischii has a level of 40%, D. maculatus at 38%, and N. rufipes at 22%. In their appearance, damages of Dermestes differ from those of N. rufipes. Larvae of N. rufipes destroy inner parts, mostly dried flesh whereas Dermestes are eating both skin and flesh. Damages of insect pests observed are both affecting the quantity and the quality of this precious commodity, which become a lost as food. It is therefore necessary to consider methods for the control of these pests. |
