Influence of killing agents and water on the capture of six Coleoptera species in probe traps

Abstract

The introduction of propylene glycol, DDVP and water inside perforated probe traps was evaluated on the basis of their effectiveness in trapping adults of six species of Coleoptera infesting stored cereals. Adults of Sitophilus oryzae, Tribolium castaneum, Cryptolestes ferrugineus, Tenebroides mauritanicus, Rhyzopertha dominica and Oryzaephilus surinamensis were placed in plastic cylindrical bins each containing 14 kg of wheat. One probe trap was then introduced into each container and the adults trapped were counted 72 h later. Experiments were conducted at two population densities, of 30 adults (approx. one insect per 0.5 kg of wheat) and 90 adults (approx. three adults per 0.5 kg of wheat) of each species per container. The highest percentage of adults trapped was observed for C. ferrugineus and T. castaneum, and the lowest for R. dominica and S. oryzae. No significant differences in number of adults captured (% of the total number of adults) was noted between the two population density levels. At the lower density, the presence of killing agents in the traps did not increase the captures significantly; on the other hand, at the higher density, the killing agents helped to increase significantly the catches of S. oryzae, T castaneum, T mauritanicus and O. surinamensis, as compared with the catches in the control traps. No significant differences were noted for C. ferrugineus and R. dominica.