Trap catch of the European corn borer, Ostrinia nubilalis, in pheromone traps in Sweden 2013-2022

The European corn borer exists as two pheromone strains using different blends of the two active compounds for sexual communication. The Z-strain is a major pest on maize and was observed for the first time in Sweden in 2010. This study monitored the occurrence of the two strains in Swedish maize fields by captures in pheromone traps during 2013-2022 to evaluate if the Z-strain is increasing in distribution and abundance and has become a threat for Swedish maize growers. In 2018, traps were placed also in areas without maize fields and Dichrorampha petiverella males were captured in these traps. Weekly catches of male European corn borer (Ostrinia nubilalis) in traps baited with different pheromone blends (E-strain, Z-strain or hybrid) and placed in maize fields in south Sweden. The experiments were performed during June-August 2013-2022. In 2018, traps were also placed in areas far away from maize fields.