Method for spore production of <i>Leptosphaeria maculans</i>

Abstract

To enable the epidemiology of Leptosphaeria maculans a pathogen of brassicas to be studied a method for producing spores was required Sporulation of L maculans was assessed on V8juice agar and PDA under two light conditions Five L maculans isolates subcultured with three replicates on each agar were incubated under continuous cool white fluorescent lights at room temperature or 1212 h lightdark at 20C After 9 days incubation colony diameter was measured and spores counted Spore suspensions were produced by pouring 10 ml of sterile water onto each colony and scraping the surface with a sterile glass rod and spores counted using a haemocytometer For all isolates colony diameter was greater on V8juice agar (372526 mm) compared to PDA (123501 mm) under both conditions Isolates subcultured on V8juice agar (97910⁶/plate) gave a higher spore concentration than PDA (35510⁵/plate) Light condition significantly affected spore production but not colony diameter as the highest spore suspension concentration was obtained from those isolates subcultured on V8 juice agar under continuous cool white fluorescent at room temperature (18610⁷/plate) while the lowest concentration was obtained from isolates subcultured on PDA at 20C with 1212 h lightdark (90010⁴/plate) The results have determined the best method for spore production for subsequent experiments