The importance of ground snow cover to the overwintering success of Aphthona flea beetles is not clearly understood. During 2001 and 2002 we studied the effect of snow and no-snow on the overwintering success of an established Aphthona flea beetle population in southeast North Dakota. The population level of Aphthona spp. entering the overwintering period and the overwintering success of the flea beetles were determined during late October and late May, respectively, of each experimental year. Soil temperature was recorded from mid-October through late May to correlate mean winter soil temperature to spring flea beetle emergence. During 2001 and 2002 experimental years, the mean spring flea beetle emergence was lower than the mean flea beetle population entering the winter. Significantly more flea beetles survived through the winter of 2000-01 when the ground was covered with snow as compared to when ground was maintained free of snow. The spring 2001 flea beetle emergence was significantly correlated with the 2000-01 mean winter soil temperature and the number of continuous subfreezing days. The spring 2002 flea beetle emergence was not significantly different between the snow- and no-snow covered treatment plots, and there was no correlation between spring flea beetle emergence and mean winter temperature or the number of continuous sub freezing days. Snow cover may enhance the overwintering success of Aphthona flea beetles spp. when the average winter soil temperature is below - 4OC.
Species 1: Coleoptera Chrysomelidae Aphthona czwalinae (flea beetle)
Species 2: Coleoptera Chrysomelidae Aphthona lacertosa
Keywords: snow cover, overwintering
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