Final diagnosis

Sclerotinia rot

Snare attack of <i><b>Sclerotinia sclerotiorum</i></b> on young lettuce plant after planting.
The outer leaves of this lettuce wilt following invasion of the petioles and main veins by <i><b>Sclerotinia sclerotiorum</i></b>.
Lettuce collar completely rotted by <i><b>Sclerotinia sclerotiorum</i></b>.  Wet weathered tissues reveal an orange hue.
Several lower leaves of this lettuce are more or less rotting, both the leaf blade and the midrib.  Dense white mycelium gradually covers partially decomposed leaf tissue.  (<i><b>Sclerotinia sclerotiorum</i></b>)
Sclerotia forming on lettuce collar.  These do not take long to melanize and harden.  (<i><b>Sclerotinia sclerotiorum</i></b>)
Detail of large elongated black sclerotia on lettuce.  (<i><b>Sclerotinia sclerotiorum</i></b>)
Portion of cucumber stalk altered, brown to brown in color, bearing in places initially white masses gradually blackening (sclerotia).  (<i><b>Sclerotinia sclerotiorum</i></b>)
White mycelial "spiral" enveloping this three-quarter rotten cucumber fruit.  (<b><i>Sclerotinia sclerotiorum</i></b>)
Canker lesion on well-developed melon stem.  It is almost completely covered by a dense white mycelium.  An orange gummy exudate is clearly visible.  (<i> Sclerotinia sclerotiorum </i>)
Wet lesion surrounding the stem of a melon stalk.  Note the presence of the fungus' characteristic white mycelium and a salmon to orange gummy ooze.  (<i> Sclerotinia sclerotiorum </i>)
Wet lesion surrounding the stem of a melon stalk.  Note the presence of the white mycelium of the fungus and some rough sclerotia.  <i> <b> Sclerotinia sclerotiorum </b> </i>.  (sclerotinia)
Detail of a rot on melon fruit, the mycelium of <i> Sclerotinia sclerotiorum </i> and its sclerotia in the process of formation.  (sclerotinia)
Après avoir coloniser une inflorescence d'aubergine, <i>Sclerotinia sclerotiorum</i> a gagné la tige qu'il a envahi sur plusieurs centimètres. Notez le dense mycélium blanc et quelques gros sclérotes noirs par endroits.
Detail of a lesion on the stem of an eggplant plant.  This one has a beige to light brown hue and shows some concentric patterns on the periphery.  (<i><b>Sclerotinia sclerotiorum</i></b>)
Eggplant fruit parasitized by <i><b>Sclerotinia sclerotiorum</b></i>, but also by secondary invaders which contributed to its liquefaction.  Note the development of the dense white mycelium especially at one end of this eggplant.
This pepper stem is surrounded by a very advanced necrotic lesion.  the very weathered stem is broken.  (<i><b>Sclerotinia sclerotiorum</i></b>)
Moist, beige-gray lesion on pepper stem.  Note the wilting of some leaves located downstream of the lesion.  (<i><b>Sclerotinia sclerotiorum</i></b>)
A longitudinal section in a lesion shows the total degradation of the internal tissues, and the presence of mycelium and large black sclerotia.  (<i><b>Sclerotinia sclerotiorum</i></b>)