Observations on the seasonal flight activity of the box tree pyralid Cydalima perspectalis (Lepidoptera: Crambidae) in the Rhine-Main Region of Hessia
The seasonal activity of wild populations of the invasive box tree pyralid Cydalima perspectalis Walker (Lepidoptera: Crambidae) was observed between 2012 and 2015 in the Rhine-Main region in Hessia. The moth flight was detected by a light trap (2012–2014) and several pheromone traps (2013–2015) at two locations. Two main flight periods were identified annually, which indicate the existence of two generations. The first flight phase was relatively weak. It began in mid June and reached its peak in mid July. It was followed by a much extended flight phase of the second generation from mid August to October with a peak in early September (calendar week 36/37). In addition to the surveillance of the flight, basic data on the sex ratio and the appearance of the two main phenotypes of C. perspectalis (white and melanic morph) were obtained. It could be shown that neither the proportions of females nor the amount of melanic moths differ significantly between the two flight phases. The proportion of melanic moths was on average 14% ± 2.9% and differed only slightly over the years. Overall, it can be stated that both trap systems are suitable for the observation of the flight activity and thus also for the proper timing of control measures. The detection of females by using light traps is not necessary for this purpose.