Influence of Different Precipitation Periods on Dendrolimus superans Occurrence: A Biostatistical Analysis

Precipitation is one of the most important abiotic factors that affect Dendrolimus superans occurrence. In this study, agrey slope-correlation model was used, and a simplified grey slope-correlation model was constructed to uncover the most crucial periods of precipitation that pest occurrence. Results revealed that thetwo models were similar; however, the simplified grey slope-correlation model required less calculative steps and was easier to operate. The calculation results revealed that the most crucial period occurred during thefirst 10 days of July (γ13 = 0.67, γ`13 = 0.69). The other precipitation periods associated with pest occurrence included thefirst 10 days of August (γ16 = 0.62, γ`16 = 0.61), the third 10 days of May (γ09 = 0.59, γ`09 = 0.62), the sec10 days of May (γ08 = 0.58, γ`08 = 0.60), and the third 10 days of August (γ18 = 0.58, γ`18 = 0.60). The less associated precipitation periods included the first 10 days of March (γ01 = 0.54, γ`01 = 0.47), the sec10 days of March (γ02 = 0.50, γ`02 = 0.49), the third 10 days of April (γ06 = 0.47, γ`06 = 0.48), the sec10 days of June (γ11 = 0.51, γ`11 = 0.48), and the third 10 days of June (γ12 = 0.51, γ`12 = 0.51). Precipitation in May (γ07 + γ08 + γ09 = 1.74, γ`07 + γ`08 + γ`09 = 1.79) and July (γ13 + γ14 + γ15 = 1.74, γ`13 + γ`14 + γ`15 = 1.79) was mostly associated with D.superansoccurrence. The findings of this study provided a simple operative model for determining the most crucial precipitation periods of pest occurrence, and these analytical methods can serve as a theoretical reference for pest forecasting and early warning, which contributes to ecological protection.© 2021Friends Science Publishers

Problems of Ecology and Forest Protection in the Irkutsk Region

The main causes of drying out and loss of forest stands in the Irkutsk region are identified, the dynamics of losses of forest territories over a tenyear period from 2007 to 2017 is presented. It was revealed that the main causes affecting the state of forest plantations are fires, diseases of woody plants, in particular coniferous bacteriosis (bacterial dropsy of Siberian cedar pine (Pinus sibirica)) and dendrophage insects (Siberian cocoonworm (Dendrolimus superans Butler)). Suggestions have been made to improve the organization and conduct of forest protection and forestry activities.

Dendrolimus superans sibiricus. [Distribution map].

A new distribution map is provided for Dendrolimus superans sibiricus (Tschetv). Lepidoptera: Lasiocampidae. Hosts: Khingan, Sakhalin and Siberian fir (Abies nephrolepis, Abies sachalinensis, Abies sibirica), Dahurian and Siberian larch (Larix gmelinii, Larix sibirica), Yeddo and Siberian spruce (Picea jezoensis, Picea obovata), fruit pine (Pinus korainensis) and Pinus sibirica. Information is given on the geographical distribution in Europe (Russia, Central Russia, Eastern Siberia, Far East and Western Siberia) and Asia (China, Heilongjiang, Jilin, Liaoning, Nei Menggu, Kazakhstan, Korea Democratic People's Republic, Korea Republic and Mongolia).