Ovipositional Preference of Pear Psylla (Homoptera: Psyllidae) for Resistant and Susceptible Pear

Abstract

Ovipositional preference of pear psylla, Cacopsylla pyricola Foerster, for selected Pyrus genotypes known to differ in nymphal feeding antixenosis was quantified in the field and greenhouse during the dormant-bud, green-tip, and fully expanded-leaf stages of bud phenology. Definite ovipositional preferences were displayed by pear psylla. Ovipositional antixenosis was particularly evident in Pyres communis L. and P. communis L. × P. ussuriensis Maxim. hybrids that were also known to have nymphal feeding antixenosis during the fully expanded-leaf stage. Although ovipositional and nymphal feeding antixenosis did show significant correlation, there were exceptions that suggest these two pear traits are independent. In greenhouse and field studies, we found that ovipositional antixenosis varied with bud phenology within pear genotypes, which indicated that ovipositional cues differed. However, several P. communis and P. communis × P. ussuriensis genotypes exhibited ovipositional antixenosis during all stages of bud phenology. Results of greenhouse ovipositional studies were similar to those observed for these pear genotypes in the field. Our greenhouse technique offers a rapid means of evaluating ovipositional antixenosis in pear genotypes compared with field studies, which are hampered by variable pear psylla populations, time, and space requirements.