High-density populations of C. chinensis can cause premature leaf drop, diminish plant growth, and reduce fruit size by sucking the sap of leaves, shoots, and fruits. In addition, they are also considered vectors of pear pathogens such as Erwinia amylovora Burrill (Hildebrand et al. 2000) and Candidatus Phytoplasma pyri (Carraro et al. 1998).