Seasonal activity of adult ticks Ixodes persulcatus P. Sch. in the eastern part of the Russian Plain.

In the TBE focal region in the eastern part of the Russian Plain the beginning of the adult I. persulcatus activity is usually registered in the last ten days of April, when the upper soil layers get warmed thoroughly up to +5 or 10 degrees C. The period of activity is dissimilar in different years, varying between 65 and 95 days. The duration of the activity period is associated with the tick number and weather of the season. The most favourable years for the activity of adult I. persulcatus are those whose climatic data correspond with mean long-term data. The temperature deviations of each year from the mean long-term values cause the change of the seasonal tick activity. The diurnal rhythm of adult I. persulcatus activity changes during the season.