Chalara thielavioides causes black root rot of carrots during long-term cold storage
M. Mayama.
Journal of Plant Pathology Volume 90 (2, Supplement) August 2008, Book of Abstract, 9th International Congress of Plant Pathology, August 24-29, 2008 Torino,Italy,. 507 pages.
2008
บทคัดย่อ
Chalara thielavioides causes black root rot of carrots during long-term cold storage
Black root rot of carrots has been one of the most common post-harvest diseases in supermarkets as well as domestic refrigeratorsinJapan. It is especially noted that root rot occurs in spite of storage at low temperatures. In carrot fields, such as inHokkaidoin the northern part ofJapan, two species,Chalara elegansandChalara thielavioideshave been detected as soilborne pathogens of black root rot. However, the pathogen isolated from black lesions oncarrots, thatwere stored at low temperature and distributed to the market, was exclusivelyC. thielavioides. Thus, the effects of temperature on the growth of twoChalaraspecies on potato-dextrose agar and the symptom development on inoculated carrot roots were examined. The data showed that mycelial growth and the formation of chlamydospores and phialospores ofC. thielavioidesoccurred even at 2.5°C and 5°C, but not withC. elegans. In fact, black rot lesions developed onC. thielaviodes-inoculated carrots, but not onC. elegans-inoculated carrots, even if stored for two months. Conversely, the growth ofC. eleganswas better than that ofC. thielaviodesat 20-30°C. The present study indicates thatC. thielavioidesis highly tolerant of low temperatures and can cause black root rot on carrots as a serious postharvest disease during long-term cold storage.