Resistance of Pyrus bretschneideri and Pyrus communis (Rosales: Rosaceae) to Pear Psylla Cacopsylla chinensis (Hemiptera: Psyllidae)

The pear psylla, Cacopsylla chinensis (Yang and Li) (Hemiptera: Psyllidae), is 1 of the most widespread and serious pests of commercial pear orchards in China. Development of effective strategies to control C. chinensis is critical for devising a sustainable integrated pest management (IPM) program. Identification of cultivars with natural resistance is included among these measures. In this study, we compared the resistance of 2 endemic cultivars of Pyrus bretschneideri Rehder (i.e., BHXS and BSL) and 2 introduced cultivars of P. communis L. (i.e., CB and CRB) to C. chinensis based on antixenosis and antibiosis under laboratory, field, and semifield conditions. The results indicated that infestations on the P. bretschneideri cultivars were significantly higher than those on the P. communis cultivars. The numbers of both summer adults and eggs were significantly higher on BSL (or BHXS) than on CB (or CRB). Although the differences in nymphal survival rate were not found prior to Day 21, the population age structure index at 14 d postinfestation was significantly higher on BSL and BHXS than on CB and CRB. Both P. communis cultivars had lower fitness and negative effects on host choice, oviposition of summer adults, and survival and development of nymphs. These introduced pear varieties may be selected as new scions, high grafting rootstocks, or a source of resistant genes in breeding programs. Their contributions can be significative in providing available materials and methods for use in IPM programs.