Final diagnosis


Alternaria brassicicola

Many cabbages show more or less spotting on their older leaves. <i>Alternaria brassicicola</i> (early blight)
A lower leaf of this cabbage shows some necrotic spots <i>Alternaria brassicicola</i> (early blight)
On this cabbage leaf, the Alternaria lesions still have a moist to greasy appearance on the periphery. The central necrotic tissues have taken on a brownish to beige tint, and are progressively splitting. <i>Alternaria brassicicola</i> (early blight)
The spots are rather circular, revealing a more or less marked yellow halo. Some have developed along the edge of the blade of this cabbage leaf. <i>Alternaria brassicicola</i> (early blight)
Detail of alternaria lesions on a cabbage leaf. Note the presence of a yellow halo, and concentric patterns on necrotic tissue. <i>Alternaria brassicicola</i> (early blight)
<i>Alternaria brassicicola</i> on bok choy cabbage leaf
On this lesion on this cabbage leaf, we can better distinguish the discreet concentric patterns present on the necrotic tissues. <i>Alternaria brassicicola</i> (early blight)
A discreet blackish mold covers the damaged tissues of this cabbage leaf. <i>Alternaria brassicicola</i> (early blight)
Plante-Navet
Early blight spots on turnip leaf. <i><b>Alternaria brassicicola</b></i>
Alternaria spore spots on turnip leaf. <i><b>Alternaria brassicicola</b></i>
Large alternaria lesion on turnip leaf. <i><b>Alternaria brassicicola</i></b>
Large sporulated spots of early blight on turnip leaves. <i><b>Alternaria brassicicola</b></i>
Alternaria spots observed on the underside of a turnip leaf. (<b><i>Alternaria brassicicola</i></b>)
Microscopie1.jpg
The spots are rather circular, revealing a more or less marked yellow halo. Some have developed along the edge of the blade of this cabbage leaf. <i>Alternaria brassicicola</i> (early blight)
Appearance of <i>Alternaria brassicicola</i> conidia as they form on cabbage leaves. (alternaria cabbage)
Detail of <i>Alternaria brassicicola</i> conidia present on the damaged tissues of a cabbage leaf. (alternaria cabbage)
Appearance of several <i>Alternaria brassicicae</i> conidia on a leaf lesion; this is another species affecting cabbage which seems less common in the tropics (cabbage alternaria)
Detail of a conidium of <i>Alternaria brassicicae</i>. Note that it is rather slender and has a longer appendage. (alternaria cabbage)