Abstract
Phoma koolunga sp. nov. is described, having been isolated from ascochyta blight lesions on field pea (Pisum sativum) in South Australia. The species is described morphologically and sequences of the internal transcribed spacer region compared with those of the accepted pathogens causing ascochyta blight of field peas. P. koolunga was distinct from Mycosphaerella pinodes (anamorph: Ascochyta pinodes), Phoma medicaginis var. pinodella and Ascochyta pisi. Under controlled conditions the symptoms on pea seedlings caused by P. koolunga were indistinguishable from those caused by M. pinodes, other than a 24 h delay in disease development. Isolates of P. koolunga differed in the severity of disease caused on pea seedlings.
This study was financed by the South Australian Grains Industry Trust. Identification of genus Phoma was confirmed by Dr Hans de Gruyter, Plant Protection Services, the Netherlands. Single conidium-derived cultures of Macrophomina phaseolina isolated from peanut were made available by Drs Michael Fuhlbohm and Malcolm Ryley, Department of Primary Industries, Queensland, Australia. Dr Tanveer Khan, Department of Agriculture and Food, Western Australia, supplied seed of WAPEA2211 from Pulse Breeding Australia.