The survival of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) and Sitophilus granarius (L.) (Coleoptera: Curculionidae) in aerated bins of wheat during british winters

Abstract

AbstractThe survival of Oryzaephilus surinamensis (L.) and Sitophilus granarius (L.) adults at the surface and centre of two 40-tonne bins of wheat, each aerated at about 10 m3/h per tonne was studied in separate experiments over three successive years. In one bin, fan operation was controlled manually, but in the other an automatic differential thermostat was used. This switched on the fan when the centre of the bin was 2°C warmer than the ambient. O. surinamensis always survived better than S. granarius in the same bin and position. Both species survived better at the surface of each bin than at the centre, and both died quicker at the centre of the bin with aeration controlled with a differential thermostat, where the grain temperature was usually less than 4°C, than in the bin with aeration regulated manually, which was mainly above 6°C. However, there was no difference between bins in the survival of either species at the surface. S. granarius always died out in both positions in both bins, but O. surinamensis always survived at the surface of both bins, and in one year it survived at the centre of the bin with aeration controlled manually.