Taxa of Leafhoppers Carrying Phytoplasmas at Sites of Ash Yellows Occurrence in New York State.

Leafhopper (Homoptera: Cicadellidae) populations were sampled and leafhopper carriers of ash yellows (AshY) phytoplasmas were identified as first steps toward vector identification. Nearly 5,000 leafhoppers were collected in malaise traps at two sites of high AshY incidence in New York state in 1996 and 1997. These insects comprised 33 taxa, including representatives of 13 genera known to contain phytoplasma vectors. The most abundant genus was Scaphoideus, with numbers about six times greater than any other genus. A total of 1,632 insects were assayed individually for phytoplasmas by polymerase chain reaction (PCR) amplification of phytoplasmal 16S rDNA and restriction fragment length polymorphism analyses of PCR products using restriction enzymes TaqI and RsaI separately. Phytoplasmas were detected in 35 insects, all but one in the subfamily Deltocephalinae. AshY phytoplasmas were detected in 19 of 812 individuals of Scaphoideus spp. and 1 of 87 of Colladonus clitellarius. Phytoplasmas of the Prunus X-disease group were detected in 1 Scaphoideus sp., 4 individuals of C. clitellarius, and 4 of 83 Scaphytopius acutus individuals. Phytoplasmas of the aster yellows group were detected in 1 of 68 individuals of Gyponana spp. and 5 of S. acutus. AshY phytoplasma carriers merit testing for possible vector ability.