The influence of the type of storage on pest infestation of stored grain in the Czech Republic

Abstract

Stored-product pests cause high economic losses by feeding on stored grain and endanger the public health by contamination of food by allergens. Therefore, the aim of this work was to explore whether the risk of infestation of stored grain by pests is different in various types of storage premises. We compared the level of infestation and the pest species composition in the two main types of grain stores in Central Europe that includes horizontal flat-stores (HFS) and vertical silo-stores (elevators) (VSS). A total of 147 grain stores located in Bohemia, Czech Republic was inspected. We found that both types of stores were infested with arthropods of three main taxonomic groups: mites (25 species, 120 000 individuals), psocids (8 species, 5 600 individuals) and beetles (23 species, 4 500 individuals). We found that VSS and HFS differ in species composition of mites, psocids and beetles. However, the primary grain pests (i.e. Lepidoglyphus destructor, Acarus siro, Tyrophagus putrescentiae, Lachesilla pedicularia, Sitophilus oryzae, Rhyzopertha dominica, Oryzaephilus surinamensis and Cryptolestes ferrugineus) occurred in both types of stores. The only exception was higher frequency and abundance of two serious beetle-pests (Tribolium castaneum, Sitophilus granarius) in HFS than in VSS. The total numbers of mite and beetle species infesting VSS and HFS was almost the same. There was higher psocid species diversity in VSS than in HFS. The difference between the total (i.e. level of pest infestation per kg of grain sample) numbers of mite and psocid individuals collected from VSS and HFS was not significant. However, the total numbers of beetle-pest individuals collected from HFS was twice the amount collected from VSS. We concluded that both types of stores are equally risky in terms of mite and psocid infestation. HFS is more risky for grain storage than VSS in terms of beetle infestations, although even the VSS structures cannot be in no way called pest-safe. The VSS and HFS microclimatic conditions (humidity, temperature) are discussed in relation to mite, psocid and beetle infestation.