Department of Industrial Entomology, Korea National College of Agriculture and Fisheries, Jeonju, Republic of Korea.
Chungnam Agricultural Research and Extension Services, Yesan, Republic of Korea.
PLoS One. 2022 Mar 9;17(3):e0265083. doi: 10.1371/journal.pone.0265083. eCollection 2022.
Even though the optimum sampling methods for invasive pests are very important in newly invaded areas, the standard sampling unit of Ricania shantungensis is still undeveloped in persimmons. Among all developmental stages of R. shantungensis, the egg has close relationship between its density and subsequent tree damage. Thus, this study was conducted to suggest an optimum sampling unit for R. shantungensis eggs in persimmons based on characteristics of its within-tree distribution pattern. The within-tree distribution pattern was characterized with 60 persimmon trees by cutting 12 branches at three vertical levels (low, middle, and high) in four horizontal criteria (east, west, south, and north) per tree. The sampling units were determined based on coefficient of variation (CV) and coefficient of determination (r2) calculated from egg mass numbers per 10 cm from the tip within a branch. In numbers of R. shantungensis egg masses, there was no significant difference (P > 0.05) horizontally, but significant (P < 0.05) difference vertically. More R. shantungensis eggs were found on terminal branches of each trunk. The 60 cm from the tip of branches in the terminal positions of each trunk was selected as the optimum sampling unit for R. shantungensis in persimmons because this unit has the lowest CV value and more than 0.9 of r2 value. Even though the optimum sample number per tree should be determined field-specifically, it would be acceptable to sample two or three branches by considering this pests' recognizable damage level. This small sampling unit could make the sampling of R. shantungensis become more economical, precise, and consistent in persimmon fields.
尽管在新入侵地区，侵入性害虫的最佳采样方法非常重要，但甜柿中仍未开发出锐丽盲蝽的标准采样单位。在锐丽盲蝽的所有发育阶段中，卵的密度与其对后续树木的损害密切相关。因此，本研究旨在根据锐丽盲蝽在柿树内的分布模式特征，提出一种适用于柿树锐丽盲蝽卵的最佳采样单位。采用 60 棵柿树，每棵树在东、西、南、北四个水平方向上，在三个垂直高度（低、中、高）上各截取 12 根枝条，以此来研究锐丽盲蝽在树内的分布模式。根据枝条梢部每 10cm 卵量计算的变异系数（CV）和决定系数（r2）来确定采样单位。在锐丽盲蝽卵数量方面，水平方向上没有显著差异（P＞0.05），但垂直方向上有显著差异（P＜0.05）。每个树干的梢部末端的枝条上发现的锐丽盲蝽卵数量更多。选择每个树干梢部 60cm 处的枝条作为甜柿锐丽盲蝽的最佳采样单位，因为该单位的 CV 值最低，r2 值超过 0.9。尽管每棵树的最佳采样数量应根据具体情况确定，但考虑到该害虫的可识别损害水平，采样两到三根枝条是可以接受的。这种小的采样单位可以使锐丽盲蝽的采样在柿树田中更加经济、精确和一致。
