First Report of Leptosphaeria biglobosa as a Stem Canker Pathogen of Brassicas in New Zealand

Phoma black leg or stem canker, caused by Leptosphaeria maculans or L. biglobosa, is an important disease of brassicas, causing significant crop losses in areas such as Europe, Australia, and North America (1). Samples collected in 2011 from canola and forage brassica (swede, kale, and turnip) crops in the main New Zealand growing regions (Southland, Central Otago, Canterbury, Hawkes Bay, and Manawatu) to identify the causal agent(s) of the characteristic stem cankers, found many isolates of L. maculans, which has been reported previously in New Zealand (2), and three isolates identified by colony characteristics as L. biglobosa. Of the latter, two isolates were from canola (Brassica napus) stem cankers from Darfield and Lincoln, Canterbury, and one was from a kale (B. oleracea) stem canker from Lincoln. An isolate (ICMP10665) of similar morphology, from the International Collection of Microorganisms from Plants (ICMP), obtained from a basal rot lesion on a cauliflower (B. oleracea var. botrytis) plant in...