Final diagnosis


Powdery mildews of cucurbitaceae

More or less dense and confluent white spots have developed on the lower leaves of this cucumber plant. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>. (oidium)
Numerous small diffuse spots dot this cucumber leaf. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>. (oidium)
On this cucumber leaf the numerous white spots are now sporulating and characteristic. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>. (oidium)
On this cucumber leaf white spots have converged and cover entire sectors of the blade. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>. (oidium)
Melon
A few circular spots, powdery and whitish, gradually extend over this melon leaf. <b><i>Podosphaera xanthii</i></b> or <i><b>Golovinomyces cichoracearum</b></i> (powdery mildew)
Very many whitish powdery spots now cover a good part of the blade of this melon leaf, some of them have merged in places. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i> (powdery mildew)
Oidium-Melon2
Oidium-Melon1
Generalized attack of powdery mildew on melon. The leaves are more or less covered by white powdery spots. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>. (oidium)
Melon leaves more or less affected by the two oidium <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>. (oidium)
This branch is entirely covered by one of the fungi responsible for melon powdery mildew, which sporulates heavily on the latter. <i> <b> Podosphaera xanthii </b> </i> or <i> <b> Golovinomyces cichoracearum </b> </i>
Young colonies of powdery mildew growing on a melon fruit as a white powdery spot. <i> <b> Podosphaera xanthii </b> </i> or <i> <b> Golovinomyces cichoracearum </b> </i> (powdery mildew)
Oidium-Courgette12
Oidium-Courgette10
Powdery mildew symptoms on courgette leaf <i><b>Podosphaera xanthi</b></i> or <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (oidium or white, powdery mildew, white mold)
Several white powdery spots have developed on the leaf blade of this <i><b>Podosphaera xanthi</b></i> or <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (oidium or white, powdery mildew, white mold)
Zucchini leaf covered by white powdery mold. <i><b>Podosphaera xanthi</b></i> or <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (oidium or white, powdery mildew, white mold)
young zucchini leaf covered by white powdery mold. <i><b>Podosphaera xanthi</b></i> or <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (oidium or white, powdery mildew, white mold)
Appearance of white powdery mold associated with powdery mildew on zucchini leaves. <i><b>Podosphaera xanthi</b></i> or <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (oidium or white, powdery mildew, white mold)
Oidium-Courgette11
Appearance of powdery white mold associated with powdery mildew on the underside of a zucchini leaf. <i><b>Podosphaera xanthi</b></i> or <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (oidium or white, powdery mildew, white mold)
A white powdery mold has also colonized zucchini leaf petioles. <i><b>Podosphaera xanthi</b></i> or <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (oidium or white, powdery mildew, white mold)
Appearance of powdery mildew spots on the upper side of a pumpkin leaf. The underlying lamina is sometimes chlorotic. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>. (oidium)
Numerous highly sporulated white spots of powdery mildew on the upper surface of a pumpkin leaf. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>.
<i><b>Podosphaera fuliginea</b></i> (<i>Sphaerotheca fuliginea</i>) et <b><i>Golovinomyces cichoracearum</i> var. <i>cichoracearum</i></b> (<i>Erysiphe cichoracearum</i>) (oïdium ou "blanc", powdery mildew, white mold) on squash 4
White powdery mildew sporulation observed on the underside of a pumpkin leaf. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>.
Installation of powdery mildew on the underside of a pumpkin leaf. Several isolated colonies develop. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>.
Microscopie1.jpg
Detail of many young mycelial colonies of <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i> growing on a courgette leaf. (oidium)
Appearance of a young mycelial colony of <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i> growing on a melon leaf. (oidium)
Observation with a binocular magnifying glass of the mycelial colonies of the 2 fungi responsible for powdery mildew makes it possible to observe their conidiophores at the end of which conidia are formed in chains. <i><b>Podosphaera xanthii</b></i> or <i><b>Golovinomyces cichoracearum</b></i>
Appearance of several short conidiophores of <i><b>Podosphaera xanthii</b></i>. (oidium)
Three conidia form the beginning of a chain at the end of a short conidiophore of <i><b>Podosphaera xanthii</b></i>. (oidium)
Sometimes the oidized leaves bear, in addition to the white down, tiny little black structures: the perithecia, organs of sexual reproduction of powdery mildews. <i> <b> Podosphaera xanthii </b> </i> or <b> <i> Golovinomyces cichoracearum </i> </b> (powdery mildew)
Detail of a cleistothecium of <i> Podosphaera xanthii </i> </b> observed under a light microscope. We can clearly see the brown wall of the latter. (powdery mildew)