Experimentální výsadba meruněk: porovnání PCR detekce fytoplazmy ESFY se symptomy onemocnění spojované s ESFY [Experimental orchard of apricots: comparison of pcr detection of ESFY phytoplasma with symptoms of disease associated with ESFY]

Abstract

Phytopathogenic bacterium ‘Candidatus Phytoplasma prunorum’, referred to as phytoplasma ESFY (European stone fruit yellows), is the causal agent of stone fruit disease with highly variable symptoms. Apricots are considered to be one of the stone fruit species sensitive for ESFY infection. The disease causes considerable economic losses due to the mortality of apricot trees. In this study, experimental apricot planting was monitored to observe the occurrence of symptoms and for molecular detection of pathogen. In the beginning, the plantation was tested using PCR method for ESFY detection. Symptoms of the disease were observed at the end of growing season in years 2018–2020. 18 % of the PCR ESFY positive apricot trees did not show any visible symptoms of the disease. Conversely, 21 % of ESFY negative apricot trees manifested at least one of the typical or non-specific symptoms of ESFY. In correlation with PCR results, we considered premature leaf fall, yellowing with leaf chlorosis and severe leaf roll in October to be the typical symptoms of ESFY. Slightly pinkish leaves and mild leaf roll were identified as non-specific symptoms. The group of symptomatic ESFY positive trees manifested the highest annual mortality rate 11.7 %. However, the group of phytoplasma symptomatic trees reduced the incidence of typical visual symptoms of ESFY in following 2 years. In conclusion, apricot trees cannot be reliably marked as positive/negative for presence of ESFY based only on symptom observation at the end of the growing season.

Keywords

• prunus armeniaca l.
• apricot
• phytoplasma esfy
• visual symptoms
• detection by pcr