Fig. 1. Disease symptoms caused by Apiognomonia errabunda. (A) Small-leaved lime trees suffering from defoliation in Aulanko, Hämeenlinna; (B) Leaves of Tilia cordata with darkened petioles collected from Kiikala, Salo; (C) leaf loss of small-leaved limes in Kiikala, Salo; (D) A. errabunda strain 3C2V representing the dominating morphotype retrieved from the leaf petioles cultured on MOS agar plate covered with a cellophane membrane. Pictures A, B and C were provided by Tapio Ykspetäjä and Seppo Lagom.

Fig. 2. Historical records of Apiognomonia errabunda in Finland and the sampled disease outbreaks on small-leaved lime in 2016. The 2016 disease outbreaks were observed in three locations (red dots). Sampling sites of A. errabunda specimens in the herbaria of University of Helsinki (LUOMUS) and University of Turku date from 1870 to 2004 and are plotted with the following symbols indicating host tree species: gray = Tilia cordata, black = Tilia × europaea or white dots = other or unknown tree species. The northern border of the distribution area of Tilia cordata in Finland is given according to Lampinen and Lahti (2016).