Figure 5; Cysts and eggs of Heterodera filipjevi infected by Monocillium bulbillosum (= Niesslia bulbillosa) in vitro. A Symptomatic cysts infected by M. bulbillosum. B Infected egg showing early stage of fungal colonisation. C–F Formation of microsclerotia in nematode eggs (arrow points at nematode’s stylet). Scale bars: 300 µm (A); 30 µm (B–F).
Figure 4; Cysts and eggs of Heterodera filipjevi infected by Monocillium gamsii (= Niesslia gamsii) exhibiting colonisation in vitro. A, B infected cysts rendered black-dotted due to fungal-colonised eggs containing microsclerotia. C, D Eggs with mature sclerotia, extracted from symptomatic cysts. E, F Individual hyphae penetrating eggshell (arrows indicate the individual hyphae; V indicates vacuole-like structures). G–M Fungal development inside the eggs. G, H Earlier stages of infection in unembryonated eggs. I, J Fungal development in the body cavity of developing juveniles where enlarged, thick-walled cells are formed and coalesce to initiate microsclerotia formation. K–M Microsclerotia developing to full size and pigmentation. N–P Pigmentation in microsclerotia from pale-olivaceous to darkly brown. Scale bars: 600 µm (A); 300 µm (B); 30 µm (C–O); 50 µm (P).
Figure 1; Naturally infested cysts and eggs of Heterodera filipjevi with Monocillium gamsii (= Niesslia gamsii), and pure cultures obtained from infected eggs. A Field collected symptomatic cysts bearing parasitised eggs. B–E Nematode eggs infected by M. gamsii. B, D Nematode eggs containing microsclerotia of M. gamsii. E An embryonated egg containing a second stage juvenile (J2) parasitised by M. gamsii (arrow points at nematode’s stylet). F A nematode egg containing microsclerotia, and hyphae growing out of it. G–H colony of M. gamsii grown on PDA. G colonies developing from three individually plated infected eggs. H A 25-d-old culture grown at 25 °C in the dark. I The surface of a five-month-old culture detailing the sclerotioid masses covering the colony surface. Single microsclerotia can be seen as little black dots at the margin of the culture. Scale bars: 800 µm (A); 30 µm (B–E); 50 µm (F); 2 cm (H); 5 mm (I).