Final diagnosis


Erysiphe necator (Powdery mildew)

Discreet white fluffy spots dot the limb of this vine leaf. <i> <b> Erysiphe necator </b> </i> (powdery mildew)
The <i> <b> Erysiphe necator </b> </i> mycelium now covers the entire blade of this leaf which becomes rather powdery and white.
Several large, powdery, whitish spots partially cover the leaf blade of this fig leaf. <i> <b> Erysiphe necator </b> </i> (powdery mildew)
Detail of large powdery and whitish spots covering the blade of a vine leaf. Superficial colonies can be clearly distinguished. <i> <b> Erysiphe necator </b> </i> (powdery mildew)
Chlorotic lesions, sometimes discreetly powdery, are visible on this fig leaf. <i> <b> Erysiphe necator </b> </i>
Discreet white fluffy spots dot the limb of this vine leaf. <i> <b> Erysiphe necator </b> </i> (powdery mildew)
The <i> <b> Erysiphe necator </b> </i> mycelium now covers the entire blade of this leaf which has a tendency to deform.
<b><i>Erysiphe necator</i></b> : Symptoms on leaf
The vine leaves affected by powdery mildew are more or less covered with a white sporulation at the origin of the name "powdery mildew".
Powdery mildew is easily recognizable on a fig leaf. This one is almost entirely powdery and strongly deformed. <i> <b> Erysiphe necator </b> </i>
The underside of vine leaves attacked by <i> <b> Erysiphe necator </b> </i> is first covered with small chlorotic spots. Powdery mildew
This oid leaf is rather rolled up; the presence of <i> <b> Erysiphe necator </b> </i> mycelium is noted on the underside of the leaf blade.
This little growing young vine shoot was affected early by powdery mildew; it shows a very characteristic <i> <b> Erysiphe necator </b> </i> flag symptom
Example of flag type symptoms on vines. <i> <b> Erysiphe necator </b> </i> (powdery mildew)
Example of flag type symptoms on vines. It can be seen that powdery mildew sporulates abundantly on this young shoot. <i> <b> Erysiphe necator </b> </i>
This young stunted branch is more or less covered by powdery mildew, its leaves have taken on a dirty gray tint, and are twitched. <b> <i> Erysiphe nectar </i> </b>
The flag symptom is characteristic of <i> <b> Erysiphe necator </b> </i>: the internodes are shortened and the leaves are curled up.
The flag symptom, initiated in the spring by the dormant <i> <b> Erysiphe necator </b> </i> mycelium in the buds, is characteristic of powdery mildew. Group A strains have long been considered responsible for this symptom; the situation on the ground would be more nuanced.
Discreet brownish lesions on twig associated with the development of <i> <i> Erysiphe cichoracearum </i> </i> (powdery mildew)
On this branch the mycelium of <i> <b> Erysiphe necator </i> </b> is still present on the necrotic lesions generated by this obligate parasitic fungus.
The brownish lesions on the twig correspond to the places where the mycelium of <i> <i> Erysiphe necator </i> </i> has developed and exercised its obligatory parasitism. (powdery mildew)
Brownish lesions on still green twig. <i> <b> Erysiphe necator </i> </b> (powdery mildew)
Brownish lesions on twig not yet ripe. <i> <b> Erysiphe necator </i> </b>
Brownish lesions on august twig. <i> <b> Erysiphe necator </b> </i>
A whitish down completely covers these bunches which will be unsuitable for vinification. <i> <b> Erysiphe necator </b> </i> 23
Many berries in this cluster are affected by grapevine powdery mildew: <i> <b> Erysiphe necator </b> </i>. We are more at the start of the attack on grape berries.
A whitish and more or less powdery down gradually covers this grape berry. <b> <i> Erysphe necator </i> </b>
These grape berries are more or less covered by the whitish and powdery down produced by <b> <i> Erysphe necator </i> </b>.
The areas of these green grape berries, colonized by the whitish down, of <b> <i> Erysphe necator </i> </b>, gradually necrotize and take on a brown to blackish tint.
This grape berry, dull and covered by a whitish down, is entirely colonized by the powdery mildew of the vine, <b> <i> Erysphe necator </i> </b>.
Many berries in this cluster are covered with powdery mildew, which gives them that dusty appearance. <b> <i> Erysiphe necator </i> </b>
The berries of this cluster are covered by a whitish powdery felting consisting of the mycelium and the numerous conidiophores and powdery conidia. <i> <b> Erysiphe necator </b> </i>
The berries of this cluster are completely covered by powdery mildew. Some of them have exploded. <b> <i> Erysiphe necator </i> </b>
Many berries in this cluster are affected by grapevine powdery mildew: <i> <b> Erysiphe necator </b> </i>. We are rather at the end of the attack on grape berries, their skin is superficially necrotic.
The skin of the berries colonized by <b> <i> Erysiphe necator </i> </b> progressively corks, making it less elastic. Thus, the berries end up splitting when they grow larger.
The skin of berries colonized by <b> <i> Erysiphe necator </i> </b> progressively suberises which makes it less elastic. Thus, the berries end up splitting when they grow larger.
<b> <i> Erysiphe necator </i> r </b> sporulates profusely on the surface of affected tissue. We can clearly distinguish many hyaline conidia produced in chains. (powdery mildew)
High concentration of conidiophores and chain conidia on the limb of a vine leaf. <i> <b> Erysiphe necator </b> </i> (powdery mildew)
Many conidiophores have formed on this leaf. They bear chain conidia and some are unusually branched. <b> <i> Erysiphe necator </i> </b> (powdery mildew)
Erect conidiophore bearing a <i> <b> Erysiphe necator </b> </i> (powdery mildew) conidium
The conidiophores of <i> <b> Erysiphe necator </b> </i> are here quite short. Like the conidia they carry, they are hyaline and septate. (powdery mildew)
Young conidia formed at the tips of the conidiophores. <i> <b> Erysiphe necator </b> </i> (powdery mildew)
A <b> <i> Erysiphe necator </i> </b> conidium has germinated; a multilobed appressorium is clearly visible.
Numerous cleistothecia of <b> <i> Erysiphe necator </i> </b>, brown to black, are well distributed locally on the blade of this leaf.
The cleistothecia of grapevine powdery mildew, <i> <b> Erysiphe necator </b> </i>, appear on the surface of the berry as numerous round superficial pits, turning black.
Several more or less mature cleistothecia are present on this vine leaf. The younger ones are still yellowish, the older ones are brown. <i> <b> Erysiphe necator </i> </b>
Several more or less mature cleistothecia are present on this vine leaf. The younger ones are still yellowish, the older ones are brown. <i> <i> Erysiphe necator </i> </i> (powdery mildew)
Long brown, septate fulchers are produced from the outer cells of the <b> <i> Erysiphe necator </i> </b> ascocarp wall. Note a few still immature asci partially emerging from the cleistothecium.
Two imature asci d'<b><i>Erysiphe necator</i></b>.
Detail of an ascus of <b> <i> Erysiphe necator </i> </b> containing at least 3 ascospores. (powdery mildew)
A few asci have been freed after squeezing a cleistothecium of <b> <i> Erysiphe necator </i> </b>.
An ascus of <b> <i> Erysiphe necator </i> </b> can contain 2 to 8 ascospores.
Aspects of asc ospores under a light microscope of <b><i>Erysiphe necator</i></b>.
<b><i>Erysiphe necator </b></i>ascospores from cleistothecia are also able to germinate.