Final diagnosis


Didymella lesions (Didymella bryoniae)

Two large dark circular spots, surrounded by a yellow halo, at the edge of the blade of a cucumber leaf. <b><i>Didymella bryoniae</i></b> (gummy stem cankers)
Circular moist lesion on the periphery, brown to necrotic in the center developing on the edge of the lamina of a cucumber leaf. <b><i>Didymella bryoniae</i></b> (gummy stem cankers)
Perithecia and black pycnidia dot this necrotic lesion initiated at the periphery of the blade of a cucumber leaf. These are the fruiting bodies of <b><i>Didymella bryoniae</i></b>.
Numerous and tiny black dots dot this necrotic lesion initiated at the periphery of the lamina of a cucumber leaf. These are the fruiting bodies of <b><i>Didymella bryoniae</i></b>.
Didymella-Concombre1
A lesion extending over several centimeters surrounds the stem of this cucumber, beige to grayish in color, it is covered with numerous and tiny black globular structures. <i>Didymella bryoniae</i> (gummy stem cankers)
<b><i>Didymella bryoniae</i></b> (chancres gommeux sur tige) 7
<b><i>Didymella bryoniae</i></b> (chancres gommeux sur tige) 9
Didymella-Concombre5
A moist, reddish-brown to blackish lesion "strangles" the lower part of this <i>Didymella bryoniae</i> cucumber stem (gummy stem cankers)
Didymella-Concombre3
Canker evolved over several centimeters at the lower part of the stem of this cucumber plant. It is completely covered with many tiny black globular structures, the fruiting bodies of <i>Didymella bryoniae</i>. (gummy stem cankers)
Didymella-Concombre2
On this canker developed on the lower part of the stem of this cucumber foot, caramel-colored gummy exudates form locally. <i>Didymella bryoniae</i> (gummy stem cankers)
<b><i>Didymella bryoniae</i></b> (chancres gommeux sur tige) 8
<b><i>Didymella bryoniae</i></b> (chancres gommeux sur tige) 14
<b><i>Didymella bryoniae</i></b> (chancres gommeux sur tige) 13
Melon
Didymella-Melon-Jaune-VANG
Didymella-melon-TCHA
The lower part of the 2 branches of this melon foot is altered over several centimeters, the injured tissues are moist and brownish. <i><b>Didymella bryoniae</b></i> (gummy stem blight)
The lesion is extensive, it now surrounds these two branches. The altered tissues, in addition to being damp, took on a brownish to black hue. Fruiting bodies are present on the tissues. <i><b>Didymella bryoniae</b></i>
Pycnidia and perithecia of <i><b>Didymella bryoniae</b></i> cover this portion of rotten stem giving it a blackish tint.
This melon foot reveals a lesion on which a dark brown gummy exudate is clearly visible. <i>Didymella bryoniae</i> (gummy stem blight)
At the level of stem lesions, a longitudinal section shows that the tissues of the cortex are altered in depth, close to the vessels. <i><b>Didymella bryoniae</i></b> (gummy stem blight)
A large moist, dark brown to blackish lesion gradually extends over this partially split melon. <i><b>Didymella bryoniae</b></i> (black rot)
On the central part of this lesion on melon fruit, there are several tiny globular structures, fruiting bodies of the parasitic fungus, as well as some gummy exudates. <i><b>Didymella bryoniae</i></b> (black rot)
The development of <i><b>Didymella bryoniae</i></b> inside this melon has given its flesh a rather characteristic black hue. (black rot)
A dark green lesion is visible on this zucchini stem. <b><i>Didymella bryoniae</i></b>. (black rot)
By cutting the stem longitudinally, it can be seen that the internal tissues are also altered. They are more or less brown in places. <b><i>Didymella bryoniae</i></b>. (black rot)
Detail of the alteration and browning of the internal tissues of a courgette stem attacked by <b><i>Didymella bryoniae</i></b>. (black rot)
Remains of shriveled petioles bearing numerous small black balls (pycnidia, perithecia); the fungus has invaded the stem which is beginning to rot. <b><i>Didymella bryoniae</i></b> (gummy stem blight)
As on cucumber, affected zucchini shows dark brown rotting and pinching of the fruit end. <i><b>Didymella bryoniae</b></i> (black rot on fruit, black rot)
Detail of a moist dark brown lesion developing at the end of the fruit. Note the pinching of the latter and its blackish coloring. <i><b>Didymella bryoniae</b></i> (black rot on fruit)
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash 12
<b><i>Didymella bryoniae</i></b>on squash leaf 1
On this squash cotyledon invaded by <i><b>Didymella bryoniae</b></i>, the fungus has produced mycelium and globular structures: its fruiting bodies. (black rot)
A few spots dot this squash fruit. They are moist, dark brown, and blackish in the center. Fruiting bodies of the fungus are also visible. (<i><b>Didymella bryoniae</i></b>) (black rot on fruit, black rot)
<b><i>Didymella bryoniae</i></b> on squash 4
A cut in this squash shows that a wet rot is developing deep down; it has a fairly characteristic black coloration. <i><b>Didymella bryoniae</b></i>. (black rot on fruit, black rot)
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash 3
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash 2
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash 5
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash 4
A moist, dark brown to black rot is developing on the part of this pumpkin in contact with the ground. <b><i>Didymella bryoniae</i></b>. (black rot)
A cut in this pumpkin reveals a wet rot progressively blackening as the mycelial development of <i><b>Didymella bryoniae</i></b> develops. (black rot on fruit)
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash10
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash 9
<b><i>Didymella bryoniae</i></b> (black rot on fruit, black rot) on squash 4
Microscopie1.jpg
Detail of tiny black globular structures, fruiting bodies of <i>Didymella bryoniae</i>, but also gummy exudates. (gummy stem cankers)
Fruiting bodies of <i>Didymella bryoniae</i> mature and strongly melanized. (gummy stem blight)
Fructifications of <i>Didymella bryoniae</i> observed under a binocular magnifying glass; they begin to melanize. (gummy stem blight)
Fructifications of <i>Didymella bryoniae</i> observed under a binocular magnifying glass; they are more or less melanized and therefore dark brown to black in color. (gummy stem blight)
Fructifications of <i><b>Didymella bryoniae</b></i> observed in profile with a binocular magnifying glass. (gummy stem blight)
Appearance of a perithecium of <i><b>Didymella bryoniae</b></i>, after squeezing it, immature asci escape. (teleomorph form)(black rot)
Bouquet of asci of <i><b>Didymella bryoniae</b></i>; in one of them 8 elongated ascospores can be distinguished. (teleomorph form)(black rot)
Aspect of fructification of <i>Didymella bryoniae</i> being formed in affected tissues. (teleomorph form)(black rot, black rot)
Appearance of a mature pycnidia: conidia are present near the ostiole. <b><i>Phoma cucurbitacearum</i></b> (anamorph form)(black rot, black rot)
Appearance of young conidia of <b><i>Phoma cucurbitacearum</i></b> (anamorph form)(black rot, black rot)
Conidia have been extruded from the ostiole, some are bicellular and characteristic. <b><i>Phoma cucurbitacearum</i></b> (anamorph form)(black rot)
Light microscope detail of septate and bicellular conidia of <b><i>Phoma cucurbitacearum</i></b>. (anamorphic form)(black rot, black rot)
Didymella-Melon3