A rapid method for detecting the predominant storage mite pest species, Acarus Siro, in the presence of grain

Abstract

The aim of this study was to prove the feasibility of developing a rapid method for detecting storage mite infestations in cereals and their derived products. This was achieved by careful raising of specific antibodies to a model species, the flour mite, Acarus siro (L.), for detection by immuno-diagnostics. The specificity of the assay was assessed against 13 species of mite, 5 species of insect pest and 5 species of fungi. Its sensitivity was determined by studying the reaction to different numbers of mites in the presence and absence of grain, and evaluated by comparison with a standard reference method, the flotation test.
The results demonstrate that the assay:-

• was specific to A. siro and showed no cross-reactivity to wheat;
• detected both dead and live adult mites of A. siro and its faeces;
• detected all life stages of A. siro and the different strains of that species tested;
• detected and quantified numbers of A. siro with and without wheat, ranging between
  0 - 1000 mites;
• gave results which correlated well with those of the flotation test
  (linear regression, r2 = 0.9091).

The work reported here has proven the potential of a laboratory-based immunoassay as a method for the rapid and sensitive detection of mites in cereal grain. We now propose to develop this method further by the production of lateral flow devices (LFDs) which can be used in the field with minimal training and have been validated for commercial use with, for example, plant viruses, bacteria, fungi and mycotoxins. We also plan to extend the applicability of the field kit to a wider range of mite species. It is envisaged that the LFD could be used throughout the food supply chain to establish the degree of contamination by mites.