The Threshold and Lag Effects of Temperature on Pine Wilt Disease Show Significant Spatial Heterogeneity

Pine wilt disease (PWD) is an economically important disease. With the increasing temperature caused by climate change, there is a concern that it may expand to regions currently at low risk, cause more serious ecological harm and economic losses in China. The pinewood nematode has an optimal temperature range for development, and historical meteorological conditions, particularly temperature, can influence its current occurrence through time-lagged effects. Lag effect is a temporally delayed effect. In order to investigate the threshold effect and lag effect of temperature on PWD, we collected province-level occurrence data in China and explored the threshold effect, lag effect, and spatial heterogeneity mechanism using a distributed lag non-linear model. The results show that temperature has a significant threshold effect and lag effect on PWD. The threshold temperatures and lag periods vary from 19.5 °C to 25.1 °C and from 1 to 3 months in different provinces in the study area. The threshold temperature shows significant spatial heterogeneity and is positively correlated with the average temperature. This study provides a theoretical basis for the prevention and control of PWD, as well as protection of forest ecological security.