Studies On Relationship Between Main Pests And Natural Enemies In ‘Baihaozao’ Tea Garden

This study had financial supported from the National Natural Science Foundation of China(30871444)and Natural Science Foundation of Anhui Province(11040606M71).The communities of main pests and their natural enemies were investigated in‘Baihaozao’ tea garden in 2015,2016 and 2020.The geostatistical method,grey system,angle cosine coefficient method and niche analysis were used to analyze the relationship between main pests and their predatory natural enemies in time,quantity and space.Then,the main natural enemies of tea garden pests were obtained.Our results provide scientific basis to reasonably protect and utilize natural enemies.The grey system and niche analysis were used to analyze the relationship between Brevipalpus obovatus Donnadieu,Monolepta hieroglyphica Mots,Empoasca vitis Gothe and their predatory natural enemies in quantity,time,and space.The first four natural enemies closely related to the three pests were comprehensively judged.The two-year results showed the first four natural enemies of Brevipalpus obovatus were Misumenops tricuspidatu(10.569),Tetragnatha syusmata(10.249),Neoscona theisi(9.635),and Tetragnatha maxillosa(9.518).The first four natural enemies of Monolepta hieroglyphica were Tetragnatha maxillosa(10.964),Neoscona theisi(10.658),Harmonia axyridis(10.758),and Tetragnatha syusmata(10.544).The first four natural enemies of the Empoasca vitis were Tetragnatha maxillosa(10.628),Clubiona japonicola(10.482),Oxyopes sertatus(9.964),and Neoscona theisi(8.614).Using the geostatistical method to obtain the variances of the semivariogram theoretical model,the gray correlation degree between the nine natural enemies and Brevipalpus obovatus、Monolepta hieroglyphica were analyzed by the grey correlation analysis method.The position of the spatial following relationship between tea garden pests and their natural enemies were comprehensively judged according to the sum of close indices.The top five natural enemies of Brevipalpus obovatus were Clubiona japonicola(1.959),Theridion octomaculatum(1.935),Harmonia axyridis(1.876),Erigonidium graminicolum(1.870)and Misumenops tricuspidatus(1.794)in turn.The top five natural enemies of Monolepta hieroglyphica were Clubiona japonicola(1.965),Tetragnatha maxillosa(1.951),Misumenops tricuspidatus(1.929),Erigonidium graminicolum(1.917)and Harmonia axyridis(1.841)in turn.The Clubiona japonicola was the first natural enemy closely related to the two pests.The range of semi-variogram theoretical model was obtained by geostatistics method,and the relationship between true bugs(Pentatomoidea),tea aphid and their natural enemies by angle cosine coefficient method.Finally,the position of the spatial following relationship between tea garden pests and their natural enemies were comprehensively judged according to the sum of close indices.According to comprehensive analysis,the results showed that the top three natural enemies closely related to tea aphid were Erigonidium graminicolum,Tetragnatha squamata and Clubiona japonicola.The first three natural enemies of true bugs were Oxyopes sertatus、Tetragnatha maxillosa and Misumenops tricuspidatus.The grey system and niche analysis were used to analyze the relationship between tea thrips(Thysanoptera)and their predatory natural enemies in quantity,time,and space in‘Baihaozao’tea garden.According to the sum of the close relationship between natural enemies and tea thrips,the dominant natural enemies of thrips were judged.The results indicated that the top four natural enemies of thrips were Theridion octomaculatum(10.890)、Tetragnatha maxillosa(9.874)、Tetragnatha squamata(9.148)and Neoscona Theisi(8.553).The t-test was used to test the population difference of main pests and their natural enemies in autumn and winter of 2020,2015 and 2016.There were significant differences between Breuipalpus oboyats and leaf beetles(Coleoptera),Araneidae(Araneae)and Clubiona reichlini Schenkel.And difference between Tetragnatha squamata in 2015 and Tetragnatha maxillosa in 2016.Compared with 2020,the difference between the Tetragnatha maxillosa in 2015,Clubiona reichlini Schenkel and Araneidae(Araneae)in two years were extremely significant,and the other differences are not significant.The main reason is that the large crown of adjacent trees and Osmanthus fragrans(Thunb.)Lour.in tea garden has an impact on the ecological environment.