Western Range Limit, Population Density, and Flight Dynamics of the Fruit Pest Grapholita inopinata (Lepidoptera: Tortricidae) in Russia

The Manchurian fruit moth, <i>Grapholita inopinata</i> (Heinrich) (Lepidoptera: Tortricidae), is an important pest of fruit crops, particularly apples (<i>Malus</i> spp., Rosaceae), and is classified as a quarantine pest in many European countries and other world regions. Until recently, this species was known only in Northeastern China, Japan, and Russia (from Eastern Siberia and the Far East). To determine the westernmost distribution of <i>G. inopinata</i> and assess its abundance, we conducted nine-year pheromone monitoring across 13 administrative regions of Russia from 2014 to 2018 and 2021 to 2024. A total of 1866 traps were deployed, capturing 31,962 <i>G. inopinata</i> specimens in 1811 traps. The species was newly detected in eight regions-seven in Asian Russia and one in European Russia (Perm Krai). These findings doubled the moth's known range on the Asian continent and extended its western boundary to 56° E in European Russia. Between 2021 and 2024, <i>G. inopinata</i> was generally found at low densities across the surveyed regions (≤10 males per trap per week), with the exception of Perm Krai, Omsk, and Novosibirsk Oblasts, where moderate abundance (up to 38 males per trap per week) was recorded. In contrast, from 2014 to 2018, moderate to high population densities (up to 94 males per trap per week), including mass occurrences (over 100 males per trap per week), were observed in Krasnoyarsk Krai, with an absolute peak capture of 303 males in one trap in June 2017. Notably, in 2015-2017, male flight activity in southern Krasnoyarsk Krai exhibited two distinct peaks: one in mid-to-late June and another from late July to mid-August, indicating the development of two generations. This is the first-ever record of a bivoltine seasonal cycle for <i>G. inopinata</i> in Siberia. These findings are critical for improving pest risk assessments and developing early detection strategies, supporting more effective monitoring and management approaches of this orchard pest.