Dispersal and flight of the stored grain pests Cryptolestes ferrugineus and Sitophilus oryzae in non-storage landscapes

The rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Silvanidae), and the rice weevil, Sitophilus oryzae (Linnaeus) (Coleoptera: Curculionidae), are serious pests of stored grain throughout the world.  The male-produced aggregation pheromones for each species were described years ago in laboratory work, but only limited testing of synthetic pheromones has been done in the field.  The four experiments reported here focused on the dispersal and flight of these two grain pests responding to semiochemicals in areas outside of grain storage facilities. Four-unit Lindgren funnel traps were used in randomized complete block design experiments.  Treatments were wheat berries, ethanol, commercial food lure blends, individual food lures and synthetic pheromones.  A bock of 4 traps each was established at each of four locations in the Manhattan, KS area.  Traps were checked every four days and trapped insects, if any, were identified and recorded. The order of the traps at each location was re-randomized after each four-day check.  The overwhelming majority of the insects collected from these experiments were not C. ferrugineus or S. oryzae, the insects of interest.  However, traps with ethanol and wheat captured many more flying insects of numerous insect species from over five orders compared to other treatments.  Future research will utilize laboratory studies of orientation by adult C. ferrugineus and S. oryzae to various stimuli toward development of monitoring tools for future field work with these pests.