Final diagnosis


Downy mildew on Cucurbitaceae (P.Cubensis)

All these cucumber leaves are more or less covered by more or less confluent chlorotic spots. <b><i>Pseudoperonospora cubensis</i></b> (mildew, downy mildew)
Another aspect of mildew spots on cucumber leaves. <b><i>Pseudoperonospora cubensis</i></b> (downy mildew)
The chlorotic spots on cucumber leaves are angular because they are delimited by the veins, eventually forming a pseudo-mosaic on the leaf blade which should not be confused with a virus mosaic. <b><i>Pseudoperonospora cubensis</i></b> (mildew, downy mildew)
On this cucumber leaf, many spots have coalesced, some are starting to turn brown and become necrotic. The blade is partially deformed. <b><i>Pseudoperonospora cubensis</i></b> (mildew, downy mildew)
Mildew stains on cucumber leaf more or less evolved. The limb is partially deformed at the places where they have merged. <b><i>Pseudoperonospora cubensis</i></b> (downy mildew)
This leaf is almost entirely covered with angular lesions. A large number of them are very evolved and therefore very chlorotic or even more or less necrotic. <b><i>Pseudoperonospora cubensis</i></b> (mildew, downy mildew)
On the underside of this cucumber leaf the angular spots are lighter, but well delimited by the veins. <b><i>Pseudoperonospora cubensis</i></b> (mildew, downy mildew)
Detail of the gray to purplish-brown down forming on the spots on the underside of the leaf blade. <b><i>Pseudoperonospora cubensis</i></b> (mildew, downy mildew)
Numerous spots reveal on the underside of the lamina a more or less discreet down, gray to purplish brown, which sometimes tends to accumulate along the veins. <b><i>Pseudoperonospora cubensis</i></b> (mildew, downy mildew)
Melon
Greasy brown to black spots dot the blades of several melon leaves. <b><i>Pseudoperonospora cubensis</i></b> (downy mildew)
Detail of necrotic, blackish and angular spots on melon leaf. A chlorotic halo surrounds them. (<i>Pseudoperonospora cubensis</i>) (downy mildew)
The brown to black greasy spots are circular to angular if they are delimited by the veins, a more or less marked chlorotic halo borders them. <b><i>Pseudoperonospora cubensis</i></b> (downy mildew)
On the underside of the blade the spots have a more livid hue. <b><i>Pseudoperonospora cubensis</i></b> (downy mildew)
Wet at first, the spots of mildew visible under the blade quickly blacken, and then become necrotic. <i>Pseudoperonospora cubensis</i> (downy mildew)
Dried down mildew spots observed under the blade of a melon leaf. (<i>Pseudoperonospora cubensis</i>) (downy mildew)
Very strong mildew attack on melon plant. Necrotic spots affect more or less many leaves. Some are completely dried out. (<i>Pseudoperonospora cubensis</i>) (downy mildew)
This leaf, affected by numerous spots of mildew, turned yellow, necrotic and curled. <i> <b> Pseudoperonospora cubensis </b> </i> (downy mildew)
Mildew chlorotic spots observed by transparency on zucchini leaf. <i><b>Pseudoperonospora cubensis</b></i> (downy mildew)
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<i><b>Pseudoperonospora cubensis</b></i> (downy mildew) on zucchini leaf 15
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Appearance of mildew spots on several Nice squash leaves. <i><b>Pseudoperonospora cubensis</b></i> (downy mildew)
Bitter cucumber leaves dotted with small chlorotic to necrotic lesions, gradually clearing up. <i><b>Pseudoperonospora cubensis</b></i> (mildew, downy mildew)
This butternut leaf is covered with a multitude of chlorotic spots. <i><b>Pseudoperonospora cubensis</b></i> (mildew, downy mildew)
These patisson leaves are covered with numerous angular chlorotic, even necrotic, often confluent spots. <i><b>Pseudoperonospora cubensis</b></i> (mildew, downy mildew)
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<i><b>Pseudoperonospora cubensis</b></i>(downy mildew) on zucchini leaf 7
Numerous sporangiophores bearing sporangia make up the greyish to mauve down visible on the underside of the blade of this melon leaf. <i><b>Pseudoperonospora cubensis</b></i> (downy mildew)
Detail of an arbuscular sporangiophore of downy mildew observed under a light microscope. Note the sporangia formed at the ends. (<i>Pseudoperonospora cubensis</i>) (downy mildew)
Detail of more or less melanized sporangia observed under a light microscope. <i>Pseudoperonospora cubensis</i> (downy mildew)