A critical re-examination of powdery mildew collections on boxelder maple (Acer negundo, Sapindaceae) in Ukraine has demonstrated a shift in fungal pathogens of the genus Sawadaea affecting this common tree and introduction of two Sawadaea species into the country. The East Asian species Sawadaea polyfida was found to have spread on this host plant within the country since the early 21^st century, largely displacing the previously dominant S. bicornis. Considering recent reports of S. polyfida in Western and Southern Europe on other maple species, specimens of powdery mildew collected on A. negundo in these regions require further critical study. In October 2025, one more species of East Asian origin, S. negundinis, was recorded on A. negundo in several locations for the first time in Ukraine. Given the potential for S. negundinis to spread rapidly within Europe, this fungus is likely to be expected in, or may have already invaded, other European countries.

Keywords: boxelder maple, distribution, Europe, invasion, powdery mildew

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