Contribution of the light filth method to the Integrated Pest Management of a flour mill

Abstract

An important contribution to Integrated Pest Management in stored-product protection can be provided by the light-filth method since it gives particular attention to the extraneous particles contaminating food (such as insects, insect fragments, mites, hairs, feather barbules, etc.), extending to the identification of the material from which they have originated or the animals and vegetables from which they derive or have been part of in the past. In this regard, semolina produced by an industrial mill (processing 500 t of durum wheat per day) located in South Italy was examined for light filth according to the method established by Italian regulation. During the investigations we verified the presence of insect fragments in 250 semolina samples collected from June 2008 to July 2009. Our results show that the number of insect fragments found in the samples (from 0 to 15 fragments per 50 g semolina) remained below the limit of 75 fragments per 50 g flour established by the Italian regulation. The fragments of arthropods found in the semolina samples had different origins. Numerous fragments came from both immature and adult insects infesting plants of wheat in fields (thrips and aphids); many other fragments belong to internal feeding insects and external feeding insects (Sitophilus spp., Rhyzopertha dominica, Tribolium spp., Cryptolestes spp., Oryzaephilus spp., and Nemapogon granellus) which are able to infest cereals during post-harvest processing or to colonize millrooms in which dusts, cereal debris, and flour residues are present. We also found fragments associable to structural pests like flies and psocids that are present in environments contaminated by mould spores and fungal hyphae. The results revealed that the fumigation of the mill realized in August 2008 did not modify the number of fragments contaminating the semolina, which remained at the same level during the 14 months of the experiment.

Keywords: Light filth, Semolina, IPM, Flour mill, Italy.