Fashionably late partners have more fruitful encounters: impact of the timing of co-infection and pathogenicity on sexual reproduction in Zymoseptoria tritici.

•Intrinsic factors affecting Zymoseptoria tritici sexuality are assessed experimentally.•The ability to reproduce sexually is partly determined by the parental genotypes.•The impact of the timing of co-infection on sexual reproduction is significant.•No adaptive compromise between pathogenicity and transmission is revealed.•The in planta crossing method opens up perspectives for epidemiological studies.