Stand Characteristics and Soil Properties Affecting the Occurrence of Kunyushan Web-Spinning Sawfly (Cephalcia kunyushanica Xiao) in Japanese Red Pine (Pinus densiflora) Pure Forests in the Kunyushan Mountains, China

Abstract

: The Kunyushan web-spinning sawfly (Cephalcia kunyushanica) is a major pest in the Japanese red pine (JRP, Pinus densiflora) pure forests in the Kunyushan Mountains of China. In this study, four stand types (ST1–4) were identified in plots of JRP pure forests, based on the pest severity index (PSI; ranging from 0–100). The order of infestation ratio in the four type stands was as follows: ST4 > ST3 > ST2 > ST1. We investigated the correlation of C. kunyushanica occurrence with stand characteristics and soil physicochemical properties in the four stand types. The results showed that all stand characteristics were different among the four stand types. Compared with infested plots, healthy (ST1) plots had a higher soil bulk density, and the differences among the groups were significant. Differences in soil water content, non-capillary porosity, and total porosity were significant among the four ST groups. The average organic matter content, total nitrogen (N), and available N were lower in ST1 plots, whereas total potassium (K) was higher compared with other ST groups. In addition, a redundancy analysis suggested that seven (total N, diameter at breast height (DBH), soil water content, bulk density, available K, zinc ion (Zn2+), and stem density) of 24 environmental variables were significantly correlated with the ordinations of C. kunyushanica occurrence. The results provide theoretical guidance for the ecological control of C. kunyushanica, and are also useful for the management of forests in areas where C. kunyushanica is a major pest and where site and stand conditions are similar.

Evaluating Dendrolimus superans (Lepidoptera: Lasiocampidae) Occurrence and Density Modeling with Habitat Conditions

“…At the macroscopic level, insect reproduction and distribution are directly or indirectly influenced by climatic factors such as temperature and precipitation [5,8,9]. Within the realm of community ecology, stand characteristics and soil properties exert a pivotal influence on the occurrence of forest pests and diseases [10]. The pest of the Siberian silk moth (Dendrolimus sibiricus) is prone to outbreaks on southwest slopes [11].…”