Fungicidal activity of 2-(1-alkenyl)-3-hydroxy-1,4-naphthoquinones and related compounds

The fungicidal activity of a series of 2-(1-alkenyl)-3-hydroxy-1,4-naphthoquinones and their acetates has been assessed against various fungi in vitro and against others, notably powdery mildews, in vivo, and the activity compared with that of analogous compounds bearing saturated side chains. Several of the compounds demonstrated a broad spectrum of activity in vitro. Whereas the presence of α-unsaturation in the side chain is essential for the in-vitro activity against the non-obligate fungi tested, it is of virtually no importance for the curative effect against Erysiphe graminis on barley. Only the corresponding acetates had activity against the latter pathogen.