Impact of Early Winter-Spring Transition on the Development Dynamics of theMoth Family Tortricidae and Host Plants

Global warming is one of the most significant characteristics of climate change. Serbia is no exception; it was noted that the daily mean air temperature and the number of days with extreme weather conditions have increased. The tropical days that used to be common for the summer months recently have been registered in May and even April.

Extreme weather events can disrupt our usual perception of the time of occurrence of the development stages of pests and growth stages of plants. Since air temperature is the main trigger of plant and harmful organism development, a warm period occurrence earlier than usual in the spring could cause the earlier emergence of the pest and the earlier start of plant growing season.

Over the past fourteen years, meteorological conditions have been measured in the plant canopies as part of the Forecasting and Warning Service for Plant Protection of Serbia (PIS) monitoring system. Extremely high winter temperatures and early winter-spring transition compared to the region's climatology are recorded, affecting plant and pest phenology dynamics. This research is focused on effects registered in the moth family Tortricidae (Lepidoptera) and their host plants.

The occurrence of different stages for the codling moth (Cydia pomonella) and apples, the oriental fruit moth (Grapholita molesta) and peach, the plum fruit moth (Grapholita funebrana) and plum, and the grape berry moth (Lobesia botrana) and grapevine, were analyzed and their association with air temperature and season transition indices. The data used in the study are gathered through the PIS monitoring network. Biological data series are collected on production plantations where protection measures were regularly applied. Biofix data, as well as timing and population of adults, are gathered using pheromone traps. Eggs and larvae presence, as well as the growth stages of host plants, result from visual inspections in the orchards and vineyards. Depending on the species, 20-40 locations were analyzed annually for each pest for 2012-2024.

Our research aims to explore the impact of extreme winter temperatures and winter-spring transitions on the development of pests and host plants. Monitoring and understanding these effects is crucial for accurately forecasting and effectively managing adverse impacts on agriculture.