Podosphaera pannosa Causes Powdery Mildew and Rusty Spot on Peach Fruits from Korea

Hyeon-Dong Shin1,*   Sung-Eun Cho1   In-Young Choi2   Kyoung-Won Seo2   

1Division of Environmental Science and Ecological Engineering, Korea University
2Climate Change Response Division, Jeollabuk-do Agricultural Research and Extension Services

Abstract

The fungus, Podosphaera pannosa, was identified in 1991 as the cause of powdery mildew symptoms on peach (Prunus persica var. persica) fruit from Korea based on the morphological characteristics of the conidial state. Recently, however, in Serbia and France, the cause of ‘rusty spot’ found on peach fruit was identified as P. leucotricha, and the cause of ‘powdery mildew’ on nectarine (Prunus persica var. nucipersica) fruit was identified as P. pannosa. To confirm the identity of the Korean pathogen, we collected four samples of powdery mildew from Korean peach fruit: three with the ‘powdery mildew’ symptom and one with the ‘rusty spot’ symptom. Morphological examination of the four samples confirmed P. pannosa as the pathogen. Internal transcribed spacer sequences of rDNA were analyzed for molecular characterization. A phylogenetic tree showed that the Korean isolates were clustered into a clade containing P. pannosa from Rosa species, with high sequence similarities of more than 99%. Thus, we showed that the powdery mildew and rusty spot symptoms on peach fruits from Korea are associated with P. pannosa

Acknowledgements

This work was supported by the BK21 Plus program in 2016-2020 funded by the National Research Foundation of Korea (NRF). This study was also carried out with the support of the “Cooperative Research Program for Agricultural Science & Technology Development (Project No. PJ0124192017)” Rural Development Administration, Republic of Korea.

Figures & Tables

Fig. 1. Symptoms on peach (Prunus persica var. persica) fruits associated with a powdery mildew fungus, Podosphaera pannosa. A, Powdery mildew symptom on a young fruit ‘Hwangdo’; B, Powdery mildew symptoms on a mature fruit ‘Hwangdo’; C, Close-up of powdery mildew symptoms on a mature fruit ‘Hwangdo’; D, Rusty spot symptoms on young fruits ‘Mihong’; E, Close-up of rusty spot symptoms on a young fruit ‘Mihong’.