A Comparison of Methods for Investigating the Quantitative Relationships Between Empoasca onukii Matsuda (Hemiptera: Cicadellidae) and its Natural Enemies

To systematically study the quantitative relationship between natural enemies and pests, this paper used grey relational analysis method, angular cosine coefficient method, fuzzy similarity priority ratio method and correlation coefficient method to analyze the closeness of the quantitative relationship between natural enemies and Empoasca onukii Matsuda in “Anjibaicha”, “Huangshandayezhong” and “Longjing 43” tea plantations. The conclusions obtained by the grey relational analysis method were used as a criterion to compare the sum of the rankings of the top three natural enemies, Plexippus paykulli, Tetragnatha squamata and Ebrechtella tricuspidata, thus comparing and discussing the similarities and differences between the conclusions obtained by the four research methods. The angular cosine coefficient method and grey relational analysis method yielded no major differences in conclusions, followed by the correlation coefficient method, with the fuzzy similarity priority ratio method yielding more varied results. According to the ranking analysis of the close relationship between the number of E. onukii and its natural enemies, Tetragnatha squamata, Hylyphantes graminicola and Ebrechtella tricuspidata are the first three natural enemies closely related to the number of E. onukii. This paper is an attempt to compare the consistency of research results of various research methods, which provides a reference for selecting research methods in analyzing the quantitative relationship between natural enemies and pests.