Relationships between Aleurocantus spiniferus Quaintance and Demotina fasciculata Baly and Their Predatory Natural Enemies in Tea Garden

In order to conserve and utilize natural enemies for comprehensive control of pests in tea garden, the seasonal variations of population quantities of two pests and their natural enemies in “Ping yang te zao” tea garden were investigated systematically. The results of a paired t-testing showed that the t-values of eight natural enemy numbers, i.e. Leis axyridis (Pallas); Misumenops tricuspidatus (Fabr.); Tetragnatha squamata (Karsch); Clubiona japonicola (Boes.et Str.); Erigonidium graminicolum (Sundevall); Oxyopes sertatus (L.Koch); Propylea japonica (Thunberg); Theridion octomaculatum (Boes.et Str.), were respectively 0.78, 1.65, 0.81, 0.16, 2.09, 1.72, 1.38 and 0.79, between the seasons of spring-summer and autumn-winter in 2010, which all were significantly lower than 2.13 (t_0.05 value), indicating that there was no significant difference between numbers of two insects and their natural enemies during the two seasons of spring-summer and autumn-winter in “Ping yang te zao” tea garden. The quantity, time and space framework of Aleurocantus spiniferus (Quaintance) and Demotina fasciculata (Baly) and their predatory natural enemies in 2010 spring-summer season and autumn-winter season were systematically studied using grey system analysis, ecological niche analysis and aggregated-intensity index analysis of spatial patterns. The synthetic ranking results indicated that in 2010 spring-summer season, the orders of main natural enemies of Aleurocantus spiniferus (Quaintance) and Demotina fasciculata (Baly) were respectively Tetragnatha squamata (Karsch), Misumenops tricuspidatus (Fabr.) and Theridion octomaculatum (Boes.et Str.), Propylea japonica (Thunberg), Leis axyridis (Pallas) and Erigonidium graminicolum (Sundevall). In 2010 autumn-winter season, the orders of main natural enemies of the two pests were respectively Tetragnatha squamata (Karsch), Misumenops tricuspidatus (Fabr.) and Clubiona japonicola (Boes.et Str.); Leis axyridis(Pallas),Misumenops tricuspidatus (Fabr.) and Propylea japonica (Thunberg). In addition, the results also showed that the λ value of gathering average of Aleurocantus spiniferus(Quaintance) was over 2 in April 24, 2010, indicating that the aggregation of pest was caused by itself. However, the λ values of gathering average of all enemies were smaller than 2, implying that the aggregation of most natural enemies was caused by different environmental factors.