Final diagnosis


Colletotrichum orbiculare (anthracnose)

On this melon leaf, leaf lesions started from the veins. Note their brown to reddish hue. </b> <i> Colletotrichum orbiculare </i> </b> (anthracnose)
Large, rather circled spots, dark at the periphery and greyish at the center are scattered on this blade. <b> <i> Colletotrichum orbiculare </i> </b> (anthracnose)
Several small oily spots appeared on this melon leaf. They gradually turn yellow and gradually become necrotic, at the same time taking on a brown to reddish tint. <i> </b> C. orbiculare </b> </i> (anthracnose)
Several young oily lesions, more or less elongated, bear a brown exudate. <b> <i> Colletotrichum orbiculare </i> </b> (anthracnose)
This recent lesion on a melon stem is wet and rather elongated. Its center is covered with orange masses characterizing the attacks of <i> </b> C. orbiculare </b> </i>.
Several elongated and contiguous lesions cover this portion of the stem. They have a pinkish salmon hue due to the presence of numerous gelatinous structures (acervuli). <i> <b> Colletotrichum orbiculare </b> </i> (anthracnose)
A few large oval, depressed spots are visible on this melon. They are covered with black dots and salmon-pink gelatinous masses (acervuli). <b> <i> Colletotrichum orbiculare </i> </b> (anthracnose)
As they evolve, the spots become concave, and are covered with salmon-pink fruiting bodies: the acervuli of </b><i> <b> Colletotrichum orbiculare </b> </i> </b>. These can be arranged in concentric circles as is the case on this melon. (anthracnose)
These anthracnose lesions on melon are very advanced; round to oval, they are brown to black in color, and acervuli and white mycelial felting have developed in the center of some of them. <i> </b> Colletotrichum orbiculare </b> </i> (anthracnose)
During particularly favorable climatic conditions, the damage observed can be impressive. The most attacked fruit is completely covered with black spots, misshapen, and begins to crumble and rot as secondary invaders have taken over. <b> <i> Colletotrichum orbiculare </i> </b> (anthracnose)
This melon fruit shows both small spots of Cladosporia located on the left, and larger spots of anthracnose on the right. </b> <i> Cladosporium cucumerinum </i> </b>, <b> <i> Colletotrichum lagenarium </i> </b>
Observation under a light microscope makes it possible to better distinguish the acervuli. They all have several brown, septate bristles, and the spores are clumped together in the form of mucus. <i> <b> Colletotrichum orbiculare </b> </i> (anthracnose)
<i><b>Colletotrichum orbiculare</b></i>