Observations on flight activity and voltinism of codling moth Cydia pomonella in western central part of Latvia in 2016-2018

Abstract: Codling moth Cydia pomonella, has been considered univoltine in Latvian conditions, with only rare isolated cases of an incomplete second generation. In the light of recent advancements on the topic of climate change, a possible shift towards more than one generation per year has to be considered. Change of voltinism would also require a shift in recommendations for codling moth management. We carried out observations on flight activity of codling moth, using traps baited with lures containing female codling moth sex pheromones. Observations were carried out in one orchard for three consecutive years and three different voltinism patterns were observed ranging from typical univoltine development in 2016 to a pattern strongly suggesting bivoltine development in 2018. Therefore our findings suggest enough developmental plasticity in codling moth to adjust its voltinism to changing meteorological factors. It stays unclear if the second generation is complete and capable for overwintering.