Effect of amended media, temperature, and light on the growth and development of Cercospora janseana
K. KAUR (1), C. Hollier (1). (1) Louisiana AgCenter, Baton Rouge, LA, U.S.A.
<i>Cercospora janseana</i> causes the fungal rice disease narrow brown leaf spot. In favorable conditions, this disease can cause more than 40% yield loss. Recent and frequent outbreaks of this disease are serious concerns for researchers and growers. Due to sparse information available related to this pathogen and disease, studies have been conducted to explore the factors affecting growth and development of <i>C. janseana</i>. Different kinds of basic media were tested: PDA, ½ PDA, ¼ PDA, water agar, corn meal agar, yeast agar, rice leaf extract, V8 (10%) and V8 (20%). Using V8 (20%) as a base media, further amendments were done with L-amino acids, vitamins and inorganic salts. Different temperature (10, 15, 20, 25, 28, 30, 32, 35 and 40°C) and light (12h Light & 12h dark, 14h light & 10h dark, 16h light & 8h dark, continuous dark and continuous light) regimes were tested to determine optimum temperature and light for its growth. Observations were recorded on mycelial growth, spore production and cercosporin production. Of the media amended with methionine, proline, thiamine has shown significant increased growth and sporulation of <i>C. janseana</i> as compared to unamended V8 (20%). Media amended with histidine increased the cercosporin production and significantly reduced the spore production. No growth was seen on 10, 35 and 40°C. Different light regimes had significant effect on the development of <i>C. janseana</i>.
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