First report of the natural occurrence of the teleomorph of Leptosphaeria maculans on oilseed rape and airborne dispersal of ascospores in Hungary

Leptosphaeria maculans (anamorph Phoma lingam) causes blackleg disease of oilseed rape. The teleomorph stage of the blackleg pathogen on oilseed rape in Hungary is reported for the first time. Airborne ascospores of the pathogen were monitored in the infected source area using a portable Hirst-type spore trap in different horizontal and vertical sampling points. Meteorological conditions influencing airborne spore dispersal of the fungus were analysed. Airborne ascospores of pathotypes A/Tox(+) and B/Tox(0) groups of L. maculans were identified using a modified germination test. A mixed population of L. maculans A/Tox(+) and B/Tox(0) groups were found in Hungary. The occurrence of the fungus on a wide range of its wild cruciferous hosts appears to be an important factor in the outbreak of the disease on oilseed rape. High relative humidity, rainfall, melting snow and moderate wind were the most important factors in the dissemination of the ascospores.