Aggregation of Agriotes obscurus (Coleoptera: Elateridae) at cereal bait stations in the field

Dusky wireworms, Agriotes obscurus (L.), aggregated in similar numbers at wheat [ Triticum aestivum L. (Gramineae) ‘Max’], oat [ Avena sativa L. (Gramineae) ‘Walderen’], barley [ Hordeum vulgare L. (Gramineae) ‘Verdin’], and fall rye [ Secale cereale L. (Gramineae) ‘Wheeler’ and ‘Prima’] cultivar bait stations containing 100 seeds planted 3 cm deep in 127-cm 2 circular bait stations. Similar levels of aggregation also occurred at 11 varieties of wheat planted at 100 seeds/127 cm 2 . When wheat, oat, barley, and the fall rye cultivars were planted at increasing density (0–180 seeds per bait station), aggregation by A. obscurus increased initially, but reached a plateau at numbers and at seeding rates specific to each grain variety as determined using the asymptotic equation y = B 0(1 – e – B 1 x ). Except for barley, this equation predicted wireworm densities within 11% of the densities actually observed at bait stations with 100 seeds/127 cm 2 . It was concluded that any of the wheat, oat, barley, or fall rye varieties would be suitable for monitoring A. obscurus wireworm populations if planted in bait stations at 100 seeds/127 cm 2 , as well as for aggregating wireworms by means of a trap crop.