The commercially available trap WB Probe II Trap have been used in laboratory to monitor insects activity in grains at 24±1°C and 70±5% r.h.. The major coleopteran pests of cereals in Italy,Oryzaephilus surinamensis (L.),Rhyzopertha dominica (F.),Sitophilus oryzae (L.) andTribolium castaneum (Herbst), were added to the grain at about 0.9 insect per kg. Two tests were prepared: in the testA insect activity was observed in spring wheatTriticum aestivum, L.; in the testB were compared in oat grainAvena sativa L., spring wheatTriticum aestivum L. and maize grainZea mays L.Significant differences in the numbers of insects collected by the traps were observed, both when compared across traps and cereal types. In all cereals considered traps trapped moreS. oryzae thanT. castaneum andO. surinamenis; the species less trapped wereR. dominica.