Evaluating the competition intensity of wandering spiders feeding on Empoasca onukii under varying cicada–spider ratios in tea plantations

This study was designed to explore differences in the competitive effects of wandering spiders under different cicada–spider ratios in tea plantations, and to provide a basis for the use of predatory wandering spiders for rational biological control. The population dynamics of Empoasca onukii and its natural enemies, the wandering spiders, were investigated in plantations of six tea cultivars, namely Anjibaicha, Huangshandayezhong, Longjing 43, Nongkangzao, Pingyangtezao and Wuniuzao, on the peak day of E. onukii emergence. Competition among wandering spiders under different cicada–spider ratios was analyzed using the gray correlation method and the competition coefficient method, and the results were then combined to derive a competition intensity index, which was then used to verify the accuracy of the results obtained. The results showed that the competition coefficients and competition intensity indices for low cicada–spider ratios were greater than those for high cicada–spider ratios on the peak day of E. onukii feeding, the differences between the two were significant at the t_0.20 level, and the most competitive wandering spiders at low and high ratios were Clubiona japonicola and Clubiona reichlini, respectively, indicating that the cicada–spider ratio had some influence on the competitive effect of the wandering spiders. The results provide a scientific basis for the study of competition between species of wandering spiders and the utilization of competitive wandering spiders against E. onukii for the protection of tea crops.