| frequency and seasonal distribution of pear psylla infected with the pear decline phytoplasma in california pear orchards. | abstract pear decline (pd) is an important disease of pyrus communis fruiting cultivars in europe, asia, and the americas. pd is caused by a phloem-limited phytoplasma that, in california, is transmitted from diseased to healthy trees by pear psylla, cacopsylla pyricola. the percentage of phytoplasma-infected pear psylla has never been assessed in the united states in field-collected insects. pear psylla were collected monthly from pd-infected trees from three orchards in northern california. in ... | 2002 | 18944248 |
| bacterial endosymbionts of the psyllid cacopsylla pyricola (hemiptera: psyllidae) in the pacific northwestern united states. | insects often have facultative associations with bacterial endosymbionts, which can alter the insects' susceptibility to parasitism, pathogens, plant defenses, and certain classes of insecticides. we collected pear psylla, cacopsylla pyricola (förster) (hemiptera: psyllidae), from pear orchards in washington and oregon, and surveyed them for the presence of bacterial endosymbionts. adult psyllids were collected on multiple dates to allow us to assay specimens of both the summer ("summerform") an ... | 2017 | 28334388 |