Pink Root of Onion Caused by Pyrenochaeta terrestris(syn.Phoma terrestris)

Kim, Yong Ki; Lee, Sang Bum; Shim, Hong Sik; Lee, Chan Jung; Kim, Hee Dae

The Plant Pathology Journal 2003;19(4):195-199.
Published online August 31, 2003.

Pink Root of Onion Caused by Pyrenochaeta terrestris(syn.Phoma terrestris)

Yong Ki Kim, Sang Bum Lee, Hong Sik Shim, Chan Jung Lee, Hee Dae Kim

Abstract

Pink root of onion occurred in the fields of the Onion Experimental Station and in the main onion cultivation area in Korea in 1998 and 1999, respectively. The casual fungus of pink root was isolated only from apricot agar. Formation of pycnidia and pycnidiospores of the fungus was highest in alternating cycles of 12 hours near ultraviolet light and 12 hours in dark condition. Its morphological characteristics and pigment formation on water agar were identical with that of Pyrenochaeta terrestris. The optimum temperature for the growth of the fungus and disease development was 25-28˚C. When onion seeds were inoculated with the spore suspension, incubated in test-tube and sown in potted soil, disease symptoms developed in onion roots 7 and 30 days after inoculation.

Key Words: Pathogenicity, pink root of onion, Pyrenochaeta terestris, sporulation