ZLV Online

Abstract

In the period of 2003 – 2011 we evaluated the population dynamics of Melolontha hippocastani Fabr. and Melolontha melolontha (L.) in four forest regions of the Czech Republic (CR). We used light traps, automatic meteorological stations and field investigations to monitor the course of swarming, species composition, abundance of the individual tribes, the sex ratio during swarming and dependence of swarming on the average daily temperatures. In the forest regions we distinguished M. hippocastani Fabr. tribes and evaluated the trend in the development of the abundance of the species monitored in the respective localities in order to specify the prognosis of cockchafer incidence and extent of damage in the future. In the between-swarming period of M. hippocastani Fabr. we monitored the development and evaluated the abundance of cockchafers in soil pits in forest stands of various age and different woody species composition. The extent of losses of seedlings in forest stands and the relationship between the amount of losses and shading of the forest soil were evaluated as well as the method of stand establishment and degree of weed infestation at the time of swarming. On the basis of the relationship between the abundance of cockchafers on the one hand and the extent of losses and the characteristics of the sample plots, especially the degree of shading and course of temperatures at swarming on the other, we deduced the conditions that influenced the female M. hippocastani Fabr. cockchafers in their selection of the locality where they laid eggs.