Seasonal abundance and vertical distribution of mites in flat storage containing wheat

The present study was carried out in a flat storeroom in central Greece, filled with approximately 60 tons of newly harvested wheat, in order to evaluate the population dynamics of stored-product mites and their predators in connection with horizontal and vertical distribution. At 15-day intervals, from July 2000 until March 2001, three replicates were taken from each sampling point at depths of 0-40, 40-80 and 80-120 cm, with a partitioned grain trier. The sampling points were divided into two zones, namely, central and peripheral. Air temperature, relative humidity, grain moisture and grain temperature were recorded during the sampling period. Twenty-four mite taxa were found, the dominant species beingTyrophagus putrescentiae (Schrank) andAcaropsis docta (Berlese). The numbers of these species varied significantly in the two zones and at the three depths. More individuals were found in the center compared with the periphery of the wheat bulk, and at the surface of the bulk than at greater depths. The highest mite population densities for the total mite species were recorded during October-November and after the middle of January.[PUBLICATION ABSTRACT]