New Outbreak of Dendrolimus sibiricus Tschetv. in Siberia (2012-2017): Monitoring, Modeling and Biological Control
I. N. PAVLOV1, Y. A. LITOVKA1,2, D. V. GOLUBEV1,3, S. A. ASTAPENKO1, P. V. CHROMOGIN2
1V. N. Sukachev Institute of Forest, SB RAS, 660036, Krasnoyarsk, Akademgorodok, 50/28
2Reshetnev Siberian State University of Science and Technology, 660049, Krasnoyarsk, Mir ave., 82
3“Russian center of forest health” of Krasnoyarsk Krai, 660036, Krasnoyarsk, Akademgorodok, 50А, block 2
Keywords: Beauveria bassianа, Dendrolimus sibiricus, биоинсектицид, вирулентность, массовое размножение, скрининг, bioinsecticide, mass reproduction, screening, virulence
Abstract
The territory of the new mass breeding of Dendrolimus sibiricius is the northernmost of the previously known in Siberia. The increase in pest numbers began in 2011-2012, 14 years after the previous mass outbreak. As a result, the area of damage to dark coniferous forests exceeded 1.4 million hectares. The reasons for the emergence of the pest population from a depressive state were insufficient moisture availability in May 2011, a severe drought in June-July 2012, and an increased average monthly temperature. A significant decrease in the vegetation index of SWVI in 2011-2012 was established. The hydrothermal regime of the spring-summer period in these years promoted the transition of the majority of the pest population to development over a one-year generation. An exceptional feature of the current outbreak is the low damage to D. sibiricus caterpillars by diseases and parasites. Favorable weather conditions and small number of natural entomopathogens contribute to the rapid spread of the pest in the northern and eastern directions. This creates a high risk of mass reproduction of D. sibiricus in dark coniferous forests, since the area of nearby dark coniferous stands that are suitable for the structure, climatic and forest-growing conditions for pest distribution is more than 2.7 million hectares. Pure cultures of the entomopathogenic fungus Beauveria bassianа were isolated from dead caterpillars of D. sibiricus . Multistage screening made it possible to select a promising strain for the creation of a long-acting bioinsecticide for preventive treatment of forests. The main selection criteria are: high virulence; high entomopathogenic activity at low temperatures (7-10 oC) and ability to solid-phase fermentation of plant waste.
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