Fig. 1

Microphotographs of light microscopy (a–c, g–i) and scanning electron microcopy (SEM) (d–f, j–l) showing the early development of sclerotia by Sclerotinia sclerotiorum, prior to the initiation stage. a, d Growth of hyphae tips (24 h). b–c, e–f Dichotomous branching of hyphae (48 h). g, h Initial formation of hyphal clusters (sclerotia primordia) and pigmentation (72 h). i–l Formation of several sclerotial primordia. Bars (a–c, g–i) 50 μm