Comparison of four methods for the detection of Coleoptera adults infesting stored wheat: efficiency and detection sensitivity

In order to evaluate trapping and standard sampling methods for Coleoptera adult detection in bulked wheat, three commercial types of traps (WBII, Pitfall Cone Trap and Grain Probe Trap) and a 2-m long grain trier (9 openings, 750 g capacity) were compared. The comparison, which took place in 9 steel bins containing wheat in Central Greece, indicated that the traps were more effective in detecting adults belonging to the 21 beetle species that were found. Traps contained up to 45 times more adults than the grain trier samples, while at the same time traps produced noticeable levels of detection sensitivity for all species found, as compared to the grain trier samples. For most species, mean trap catches in WBII and Pitfall Cone traps were significantly higher than the means of the other two methods. The correlation coefficient values between trap catches and adult numbers in samples were not significantly different than zero, indicating that the effort to relate trapping to absolute estimation sampling methods is a very complex procedure.