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Báo cáo lâm nghiệp: "Ecological conditions influencing the localization of egg-laying by females of the cockchafer (Melolontha hippocastani F.)"

Tuyển tập những bài báo cáo nghiên cứu khoa học hay nhất được đăng trên tạp chí JOURNAL OF FOREST SCIENCE đề tài: Ecological conditions influencing the localization of egg-laying by females of the cockchafer (Melolontha hippocastani F.). | JOURNAL OF FOREST SCIENCE 53 2007 Special Issue 16-24 Ecological conditions influencing the localization of egg-laying by females of the cockchafer Melolontha hippocastani F. M. SvESTKA Forestry and Game Management Research Institute Jtloviste-Strnady Znojmo Czech Republic ABSTRACT We explored the ecological conditions which influence the female Melolontha hippocastani F. in their selection of the locality for laying eggs. In the region of mass outbreak of M. hippocastani in the south-eastern part of the Czech Republic in selected experimental sample plots including 1 to 8 year-old forest plantations we explored the extent of losses caused by white grub feeding and the relation between the extent of the damage and the individual characteristics of the experimental plots. The relation between the extent of the damage and the method of establishment of the stands and degree of weed infestation at the time of swarming was evaluated statistically. The daily temperatures at the time of M. hippocastani swarming were recorded by means of automatic meteorological stations. A light trap was used to monitor the course of swarming. Keywords forest protection Melolontha hippocastani F. white grub feeding losses in forest plantations In the regions of mass outbreak the Melolontha hippocastani F. white grub feeding on roots causes considerable damage to plants of forest tree species especially pine oak linden and others sometimes destroying as much as 100 . The damage appears in 1 to 10 year-old forest plantations in the period when the 2nd and 3rd white grub instars are developing Zaruba 1956 Svestka Kapitola 2004 . In the Czech Republic at the present time M. hippocastani has gradated on ca 10 000 ha of forest soil and the area of destroyed forest plantations in the individual years ranges from ca 50 to 300 ha Svestka 2006 . That means that in the most seriously affected regions forest regeneration has been considerably hampered causing heavy economic losses amounting to .