The influence of number of generations on the dynamics of lime leaf miner Phyllonorycter issikii (Kumata, 1963) (Lepidoptera, Gracillariidae) in Udmurtia.
The influence of the number of generations on the dynamics of lime leaf miner Phyllonorycter issikii (Kumata, 1963) was investigated for the first time on four sample plots in the city of Izhevsk (Udmurtia) within the period from 2001 to 2020. The existence of the second generation of the miner depends on the climatic features of the season. The second generation of the miner was observed under the condition that the first generation of the species managed to complete its development in the last ten days of June. If this happened in July, there was no second generation. The variability of phenology influences the dynamics of the invasive species. The density of miner population in limes grew in the current year if in the previous season there was only one generation of the miner. The figure fell if in the previous season there were two generations. The reduction of Ph. issikii density per year with two generations could have occurred owing to a decrease in life span and the actual fecundity of females, as well as the survival rate of the second generation of the miner. This led to a significant reduction in the number of wintering moths.