Population dynamics and distribution of beet webworm Loxostege sticticalis L. (Lepidoptera, Crambidae) in Buryatia

Weather-climatic conditions in the period of three last outbreaks of Beet webworm are analysed. It is established that in the years of outbreaks, in the period of flight of the first generation (second half of July) there are optimal conditions on combination of heat and humidity (hydrothermal index of Selyaninov higher 0,9). The complex analysis of biological indexes of Beet webworm during the period of its low population density on territory of Buryatia is first produced. At the low values of in 2013 (HIS of July 0,37), and 2014 (HIS of July 0,21) in 2015 the quantity of Beet webworm moth becomes extra-low and he reveals singly, and only by the individuals of summer generation. In 2015 HIS of July 0,71 made, that in totality with more developed snow-cover, than in previous years drove to 2016 to the increase of abundance of the survive the winter stage of Beet webworm - to 1-2 specimen/350 m2. During realization of experiment on the study of conditions of wintering and survivability of object of researches, ascertain that to 15-20 percents of diapausing caterpillars arrive at the adult, normally developed stage, here the percent of forming of the developed cocoons makes 66-82%. Distribution Beet webworm being in Buryatia on north periphery of range limited, presumably, by the changes of temperature and humidity.