Effect of different culture media on growth and sporulation of Alternaria dauci causing carrot leaf blight

Abstract

Alternaria leaf blight is most common and devastating disease in carrot plant caused by deuteromycotina fungi, Alternaria dauci. A total of 11 solid culture media were tested to assess their effect on cultural characters and sporulation of A. dauci and results revealed that mean colony diameter was significantly highest on PDA (90.00 mm), followed by Potato carrot agar (75.67 mm), Oat meal agar (70.67 mm), carrot root agar (62.41 mm), Carrot leaf extract agar (54.00 mm), Richard’s agar (51.67mm) and Czapek’s dox agar (50.67mm), Radish root extract agar (45.50mm), Ashby’s agar (44.67mm) and V8 juice agar (39.33mm). The colony growth produced mostly circular and with cottony or cushiony to carpet like mycelial mat. Colony colour varied from white, grayish-white, and olivaceous green to black. At sporulation Oat meal agar and Potato dextrose agar exhibited excellent (++++) sporulation. Whereas, it was poor (+) on Radish leaf extract agar and Richard’s agar. Potato dextrose agar was reported as most suitable culture medium for growth and sporulation of Alternaria spp.