title: Effect of climate change on sporulation of the teleomorphs ofLeptosphaeriaspecies causing stem canker of brassicas.
abstract: Leptosphaeria maculans and L. biglobosaare closely related sibling fungal pathogens that cause phoma leaf spotting, stem canker (blackleg) and stem necrosis of oilseed rape (Brassica napus). The disease is distributed worldwide, and it is one of the main causes of considerable decrease in seed yield and quality. Information about the time of ascospore release at a particular location provides important data for decision making in plant protection, thereby enabling fungicides to be used only when necessary and at optimal times and doses. Although the pathogens have been studied very extensively, the effect of climate change on the frequencies and distributions of their aerially dispersed primary inoculum has not been reported to date. We have collected a large dataset of spore counts from Poznan, located in central-west part of Poland, and studied the relationships between climate and the daily concentrations of airborne propagules over a period of 17 years (1998-2014). The average air temperature and precipitation for the time of development of pseudothecia and ascospore release (July-November), increased during the years under study at the rates of 0.1 °C and 6.3 mm per year. The day of the year (DOY) for the first detection of spores, as well as the date with maximum of spores, shifted from 270 to 248 DOY, and from 315 to 265 DOY, respectively. The acceleration of the former parameter by 22 days and the latter by 50 days has great influence on the severity of stem canker of oilseed rape.
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszynska 34, 60-479 Poznan, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Kaczmarek
authors.affiliation: Institute of Agricultural and Forest Environment, Polish Academy of Sciences, Bukowska 19, 60-809 Poznan, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Kedziora
authors.affiliation: DuPont Poland Ltd., Postepu 17b, 02-676 Warsaw, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Brachaczek
authors.affiliation: Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ UK.
authors.forename: Akinwunmi O
authors.initials: AO
authors.lastname: Latunde-Dada
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszynska 34, 60-479 Poznan, Poland.
authors.forename: Sylwia
authors.initials: S
authors.lastname: Dakowska
authors.affiliation: Institute of Agricultural and Forest Environment, Polish Academy of Sciences, Bukowska 19, 60-809 Poznan, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Karg
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszynska 34, 60-479 Poznan, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Jedryczka
keywords: Aerobiology; Blackleg; Climate change; Oilseed rape; Spore concentration; Stem canker