Erysiphe cornicola, a Powdery Mildew Occurring on Cornus controversa in Korea

In Young Choi¹ Lamiya Abasova¹ Joon Ho Choi¹ Ji Hyun Park² Hyeon Dong Shin^1,3,*

¹Department of Agricultural Biology Jeonbuk National University,Jeonju,54896,Korea
²Department of Forestry Environment and Systems Kookmin University Seoul 02707 Korea
³Division of Environmental Science and Ecological Engineering Korea University Seoul 02841 Korea

Abstract

In Korea, Cornus controversa and C. florida are known as hosts of Erysiphe pulchra from section Microspharea of the genus Erysiphe. However, recent molecular-phylogenetic analyses on the internal transcribed spacer regions and large subunit gene of the rDNA revealed that the Erysiphe powdery mildew on C. controversa in Japan is in fact E. cornicola. To assess the taxonomic status of Erysiphe–C. controversa association in Korea, isolates collected since 1987 were investigated and consequently identified as E. cornicola based on molecular–phylogenetic analyses and new morphological traits. To our knowledge, this is the first study to confirm the presence of this powdery mildew in Korea.

Figures & Tables

Fig. 1.Erysiphe cornicola powdery mildew on Cornus controversa . A: The powdery mildew infects the young leaves of Cornus controversa . B: Numerous chasmothecia formed on the lower leaf surface. C: Close-up view of chasmothecia formed on the leaf. D, E: Multilobed appressoria (arrows) formed on the hyphae. F-H. Young conidiophores. Note the round apex and long foot-cells. The arrow points to a slightly displaced basal septum. I-L: Conidiophores. Three conidiophores were formed on a hyphal cell (L). M, N: Primary conidia with apically rounded and basally subtruncate ends. O: Conidia. Note small oil drops. P-R: Conidia in germination. S: Chasmothecium with seven asci and 17 appendages. T-V: Chasmothecial appendages. W: Asci. Note eight ascospores each.