Transmission of ‘Candidatus Phytoplasma pyri’ by naturally infected Cacopsylla pyri to peach, an approach to the epidemiology of peach yellow leaf roll (PYLR) in Spain

Abstract

Peach orchards in the northeast of Spain were severely affected in 2012 by a previously unreported disease in this area. The symptoms included early reddening, leaf curling, decline, abnormal fruits, and in some cases death of the peach trees. All the infected peach samples were positive for ‘Candidatus Phytoplasma pyri’, but none were infected by the ‘Ca. Phytoplasma prunorum’. In this work, potential vectors able to transmit ‘Ca. Phytoplasma pyri’ from pear to peach and between peach trees were studied and their infective potential was analysed at different times of the year. Transmission trials of the phytoplasma with potential vectors to an artificial feeding medium for insects and to healthy peach trees were conducted. Additionally, isolated phytoplasmas were genetically characterized to determine which isolates were able to infect peach trees. Results showed that the only insect species captured inside peach plots that was a carrier of the ‘Ca. Phytoplasma pyri’ phytoplasma was Cacopsylla pyri. Other insect species captured and known to be phytoplasma transmitters were present in very low numbers, and were not infected with ‘Ca. Phytoplasma pyri’ phytoplasma. A total of 1928 individuals of C. pyri were captured in the peach orchards, of which around 49% were phytoplasma carriers. All the peach trees exposed to C. pyri in 2014, and 65% in 2015, were infected by ‘Ca. Phytoplasma pyri’ 1 year after exposure, showing that this species is able to transmit the phytoplasma to peach. Molecular characterization showed that some genotypes are preferentially determined in peach.

Esterase, Glutathione S-Transferase and NADPH-Cytochrome P450 Reductase Activity Evaluation in Cacopsylla pyri L. (Hemiptera: Psyllidae) Individual Adults

“…6 Population reared in laboratory during 14 generations without any pesticide pressure. 7 Population reared in laboratory during 14 generations selected with increasing concentrations of cypermethrin.…”

“…Other indirect damage in Spain and the Mediterranean region transmitted by C. pyri includes the diseases pear decline and peach yellow leaf roll caused by the phytoplasma “ Candidatus Phytoplasma pyri” [ 4 ]. Both diseases involve yellowing, the progressive loss of tree vigor and production and, in some cases, the collapse and death of trees [ 5 , 6 , 7 ].…”

Vector transmission and epidemiology of ‘Candidatus Phytoplasma pyri’ in Austria and identification of Cacopsylla pyrisuga as new pathogen vector

“…Just as in our study, low infection rates were recorded between June and August followed by a significant increase in September and some decrease in October. The decrease in October was attributed to the emergence of the overwintering generation (Garcia Chapa et al 2005;Sabaté et al 2018). The observed fluctuation in the course of the year can probably be attributed to two causes.…”

Molecular diversity of ‘Candidatus Phytoplasma’ species in pome and stone fruits in Turkey

“…P. pyri´. Moreover the transmission of the pear decline phytoplasma to peach with C. pyri was demonstrated (Sabaté et al 2018).…”