Some Peculiarities of the Long-Term Dynamics of the Day's Absolute Maximum and Maximum Temperatures and the Emergence Rate of Adult Apple Ermine Moths (Yponomeuta Malinellus Zell.) in Lithuania

Abstract

The current paper presents the analysis of the dynamics of the day.s absolute maximum and minimum temperatures in Vilnius in different years of the 20th century and its influence on the emergence rate of adult apple ermine moths in the last three decades. The range of the absolute minimum and maximum temperatures of the day varied from -35 to +35°C. The changes in the course of emergence of adult apple ermine moths and the trends of the long-term dynamics of the day.s temperatures were thoroughly investigated during 28 vegetative seasons of the period 1973–2000. The period of the emergence of adult apple ermine moths lasted from 15 to 35 days. The time of emergence varied from 0 to 25 days. The emergence of adult apple ermine moths occurred within the range from the end of the first ten-day period of June till the middle of the first ten-day period of August. Earlier emergence of adult apple ermine moths was registered in 1984. Since 1998, the emergence of adult individuals has occurred even earlier.