Occurrence of stone fruit yellows phytoplasma disease (Candidatus phytoplasma prunorum) in Hungary and Central Europe

Abstract

Plant diseases caused by phytoplasmas have an increasing importance all over the world for fruit growers. Lately, phytoplasma diseases occur on many fruit species and are responsible for serious losses both in quality and quantity for fruit production. Apricot phytoplasma disease (Candidatus Phytoplasma prunorum) was reported first from France in Europe in 1924. Then, the pathogen spread in all European apricot-growing areas. In 1992, the disease was identified in Hungary first. Based on the growers' signals, serious damage of Ca. Phytoplasma prunorum (Seemüller and Schneider, International Journal of Systematic and Evolutionary Microbiology, 54, 2004, 1217–1226; formerly: European stone fruit yellows (ESFY) phytoplasma) could be observed in several stone fruit orchards in the famous apricot-growing area nearby the town of Gönc, northern Hungary. Field examinations were started in 2009 in the infested stone fruit plantations in Borsod-Abaúj-Zemplén County, mainly in Gönc region, which is one of the most important apricot-growing areas in Hungary, named “Gönc Apricot-growing area”. Our goals were to diagnose the occurrence of Ca. Phytoplasma prunorum on stone fruits (especially on apricot) in the North Hungarian growing areas by visual diagnostics and to confirm data by laboratory polymerase chain reaction (PCR)-based examinations. All the 40 collected samples were tested in laboratory trials and in 22 samples from apricot, peach, cherry, sour cherry and wild plum were confirmed the presence of phytoplasma (ESFY). Field investigations were done in a western Romanian apricot plantation, and the presence of apricot phytoplasma disease was confirmed. It was the first finding that Ca. Phytoplasma prunorum occurred in the western part of Romania. On the basis of these observations, it seems evident that the notable losses caused by Ca. Phytoplasma prunorum is a new plant health challenge for fruit growers to manage, especially for apricot producers in Hungary and other central European countries.