Pine web-spinning sawfly hazardous young pine wood pest in Asian part of the Russian Federation

Pine web-spinning sawfly Acantholyda posticalis is a hazardous pine pest in European Russia and Siberia. Its mass outbreaks cover young pine woods mainly plantations and in some regions occur practically every year. Outbreak coefficient that indicates how often outbreaks occur in specific regions is offered outbreak shaping frequency. Data on outbreak area dynamics in Siberian territory over 1995-2015 has been analyzed. It was found that over 21 year period in this part of Russia this phytophage outbreaks occurred more often and in big areas in the Cheljabinskaya and Kurganskaya regions and The Altay territory. Outbreak evolution potential (Q) that is defined through division of maximum fixed outbreak area in a region by its minimum fixed area has been offered to characterize outbreak shaping opportunities and scale. It is shown that in regions with the highest outbreak coefficient there is the greatest outbreak evolution potential that is big danger for forestry. In particular more attention should be paid to pine web-spinning sawfly population variation and operations to protect forests from damage by the pest larvae taken in these regions.