Diatomaceous earth to control Cryptolestes ferrugineus (Coleoptera : Cucujidae) in stored barley in farm granaries

Granary trials to determine the efficacy of an enhanced diatomaceous earth (DE) formulation (Protect-It(TM)) at 0.15 kg DE/t grain to control grain-fe eding beetles in barley, Hordeum vulgare L. (Poaceae), were conducted at Gl enlea, Manitoba. During the test, the grain moisture content ranged from 11 to 13%, and grain temperature ranged from 27 to 2 degrees C. The bulk dens ity of barley was reduced 10-20 kg/m(3) by the addition of diatomaceous ear th. Adults of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), were released onto the top surface of the grain of each granary, producing an average density of approximately 4 insects/kg grain. Using Berlese funne ls to extract insects from grain samples there was a 95% reduction in adult s and an 80% reduction in larvae found in treated grain compared with untre ated grain, 1 month after releasing insects into the grain. There was a 95% or greater decrease in the total number of insects caught with probe pitfa ll traps in the treated barley compared with the untreated barley for all;s ampling dates. For the confined populations, 200 adult C. ferrugineus or Tr ibolium castaneum (Herbst) (Coleoptera: Tenebrionidae) (red flour beetle) w ere held in screened jars in the grain until the end of October, and there was over a 99% reduction in both insect species, compared with insects held on untreated grain. These results indicate that this diatomaceous earth fo rmulation can control C. ferrugineus in barley in granaries at 0.15 kg DE/t grain.