Description of fungi


Phaeomoniella chlamydospora is also associated with Petri's disease ("slow-dieback") which is present in Europe, Australia, South Africa and the United States. Affected by this disease, the young vines show poor vegetative development, their leaves chlorose and gradually dry out on all the branches, leading to a slow decline of the strain. P. chlamydospora is also linked to dieback occurring on kiwifruit ( Actinidia deliciosa ).

  • The conidiophores are simple and cylindrical, brownish-green in color and thick-walled at their base, their color is lighter at their tip. They are surmounted by a conidiogenic cell (phialide) lighter, ampouliform and elongated, terminated by a collar (figures 1, 2 and 4). The conidia are subhyaline, oblong-ellipsoid obovate to right, grouped in glomerulus. They measure 3-4 x 1-1.5 micrometers (Figure 2). Of chlamydospores globose to sub-globular (Figure 3), olive to dark green (7-15 micrometers long), isolated or in short chains are formed in more or fewer depending on the strains.
  • Of pycnidia were sometimes produced on certain culture media and found in the vineyards on the vines.
  • Isolation, storage on artificial medium : slow growing fungus. The colonies measure barely 1 cm after one week of incubation at 25 ° C. on malt-agar medium. They quickly take on a light green color and then turn olive gray to olive black (Figures 4 and 5).

Phaeoacremonium aleophilum is usually present in its asexual form in the vineyard. The sexual form has been observed in natura on vines in California.

  • The conidiophores are simple, frequently reduced to single conidiogenous cell which is subterete to closely ellipsoid (Figures 6 to 8). The conidia are hyaline, oblong-ellipsoid to allantoic, measuring 3-4.5 x 1.5-2.5 micrometers (Figure 7). No chlamydospore is formed.
  • Isolation, storage on artificial medium : c mushroom with relatively slow growth, the mycelial colonies measuring 1 to 2 centimeters after one week of incubation at 25 ° C. on malt-agar medium. These have a beige to honey tint (Figures 8 and 9) and produce a yellow pigment that diffuses into the medium 

Fomitiporia mediterranea is a basidiomycete described as a new species associated with esca in Mediterranean vineyards, responsible for the terminal degradation of wood ("white rot" or decay). Its fruiting on the vine is identical to that produced by Fomitiporia punctata (spotted phellin). It is for this reason that identification confusions have taken place in the past. These two fungi form adhering wood- carpophores (Figure 10), flat and fully resupplied, pulvinate, with a lighter margin. Beige to brown in color, they can reach several centimeters in diameter and millimeters thick on the vine.

Stereum hirsutum produces carpophores (Figure 11) initially as circular crusts, partially peeling off and undulating, 2-10 cm long and 1-3 cm wide. Their color evolves: first sulfur yellow, with orange concentric zones, they take on a grayish tint, felted with white hair, with a lobed and wavy margin of bright yellow color in young subjects. They are 1 to 2 mm thick; they are therefore quite thin but hard, and tenacious. The hymenium is smooth, ocher-yellow to slightly orangey yellow. This fungus can be cultivated on an artificial medium (figures 12 and 13).

Last change : 04/20/21
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