First Report of Black Spot Caused by Alternaria alternata on Grafted Cactus

Choi, Min Ok; Kim, Sang Gyu; Hyun, Ik Hwa; Kim, Jeong Ho; Cho, Chang Hui; Park, Myung Soo; Kim, Young Ho

doi:2010.26.1.80

Plant Pathol J > Volume 26(1); 2010 > Article

The Plant Pathology Journal 2010;26(1):80-82.
DOI: https://doi.org/10.5423/PPJ.2010.26.1.080 Published online March 31, 2010.

First Report of Black Spot Caused by Alternaria alternata on Grafted Cactus

Min Ok Choi, Sang Gyu Kim, Ik Hwa Hyun, Jeong Ho Kim, Chang Hui Cho, Myung Soo Park, Young Ho Kim

Abstract

A stem spot disease was observed on Gymnocalycium mihanovichii (Korean name: Bimoran), a scion of graftcactus, in major growing areas of Goyang and Eumseong, Korea during 2008 and 2009. Typical symptoms were initial blackish brown lesions produced mainly on areoles and scars of injured stem tissues, gradually becoming large black spots. A causal organism isolate CD2-7A isolated from the infected stems was identified as Alternaria alternata based on its morphological characteristics and confirmed by the DNA sequencing analysis of ITS, glyceraldehydes-3-phosphate dehydrogenase (gpd), and allergen Alt a1 (Alt a 1) genes. Artificial inoculation of the fungal isolate CD2-7A produced the same rot symptoms on the cactus stems, from which the same fungus was isolated and identified. This is the first report of the black spot caused by A. alternata in the grafted cactus.

Key Words: Alternaria alternata, graft-cactus, Gymnocalycium mihanovichii, pathogenicity