We have been studying the delay since 1997." We first observed that there was a delay in the release of
ascospores from the remaining overwintering cleistothecia such that release did not occur even though conditions were suitable until a period of warm weather occurred.
The
ascospores were reddish purple, lenticular, 5-6 x 3-4 [micro]m, and smooth.
The
ascospores were extruded in creamy white colored masses deposited around the ostiole.
Isolates were obtained from endophyte-infected plants collected at 10 different sites in Switzerland (see [ILLUSTRATION FOR FIGURE 1 OMITTED] for locations) and were isolated from surface sterilized tissues, as described by Leuchtmann and Clay (1988), or as single
ascospores (Table 1).
The culture was examined under microscope after 48 h incubated, with
ascospore considered germinated when the length of the germ tube was equal or greater than the diameter of the conidia.
aestivum, produce ascomata with a basal cavity and, in others, the relative amount of phenoliccomponents is rather high"; 3) about
ascospore shape, Riousset et al.
The infections from germinating
ascospores occur as discolored chlorotic spots on the surface of basal leaves on the vine.
Key words: Cleistothecia,
ascospores, Coniochaetaceae, Coniochaetidium.
During favorable conditions, the sclerotia can germinate and produce infectious hyphae that can directly infect host plants, or else the fungus can develop carpogenically to produce windborne
ascospores that can infect crops perpetuating and expanding the disease cycle.
The family is characterized by flattened and scutate ascomata (thyriothecia), wich are usually ostiolate and develop superficially or in the cuticle of the living host's leaves; the peridium is dark coloured, mostly bluish-green, bluish-black or brown, and has a non-radiate, often meandrous interwoven cells structure (textura epidermoidea); the asci are bitunicate, clavate to cylindrical, ovate or saccate, and the
ascospores are hyaline, long clavate with mostly more than two transverse septa; the pseudoparaphyses are narrowly cellular and tend to deliquesce in mature specimens and are not always present (Batista, 1959; von Arx & Muller, 1975; Wu et al., 2011; Hyde et al., 2013; Hongsanan et al., 2014).