Gypsy moth in Serbia: Status and prospects
Size and frequency of outbreaks are connected to tree species composition in Serbian forests with more than 30 % of oak forests, which are the most suitable for gypsy moth development. We would like to emphasize the role of Turkish oak in Gypsy moth outbreak in Serbia. This tree species could be found in mixed forest with other oak species in lowland and in highland forests, but also mixed with other broadleaved species. It has highest share in wood volume and area distribution among oaks in Serbia. Gypsy moth has shortest development, higher growth, consumption rate, assimilation efficacy and fecundity on Turkish oak than other oak species in Serbia. Also, climatic conditions go in favor for Gypsy moth outbreaks. Analyzing the climatic data, we have found significant correlation between deviation from normal precipitation during summer months and Gypsy moth population density in the area of Belgrade for the period after the World War II. On the other hand, we don’t have monitoring system effective enough to predict outbreaks in its early phase.
According to the climate change scenarios, our part of Europe will be much more affected by drought in the future. The frequency of Gypsy moth outbreaks and the forest area that will be affected by Gypsy moth would be enlarged in coming decades and we can expect much more defoliation. As we aren’t able to change tree species composition and to avoid climatic conditions that are favorable for Gypsy moth development, we must establish an effective monitoring system to predict outbreak in its early phase, and thus decrease the damage caused by this pest.
The solution might be system based on pheromone traps network for early detection of Gypsy moth outbreak, similar to the Slow the spread program in the USA. For that purposes, we analyzed numerous articles and other available data about the Gypsy moth in last seventy years, especially maps of the past Gypsy moth outbreaks that were available. After these maps were overlapped with each other and polygons representing each gradation intersected, the areas (polygons) with different frequency of gypsy moth occurrence during these six gradations were formed. Based on the frequency of occurrence, zones with different risk levels for gypsy moth occurrence were established. Areas (polygons) with highest risk level are those in which gypsy moth occurred 5 or 6 times during the period from 1945-2013, total of 59.221,71 ha. Areas (polygons) with medium risk level are those in which gypsy moth occurred 3 or 4 times, total of 489.821,13 ha. The lowest risk level are those of the polygons with frequency of gipsy moth occurrence of 1 or 2, total of 1.540.013,25 ha. In the future, zones with higher risk should be more intensively monitored by pheromone traps. Establishing zones with different risk levels should help defining different intensity of monitoring in the future.
