Final diagnosis


Downy mildew of Solanaceae (P. infestans)

Downy mildew attack on tomato apex. The tender tissues have blackened and the apex is surrounded by an extensive lesion, at first moist, becoming progressively necrotic. The veins of the proximal leaflets begin to be affected. <b><i>Phytophthora infestans</i></b> (downy mildew)
Several young tomato leaflets from this apex are oily, livid, or even blackish and necrotic. <b><i>Phytophthora infestans</i></b> (downy mildew)
Several large, initially oily and blackish, now necrotic spots are clearly visible on the leaflets of this tomato leaf. <b><i>Phytophthora infestans</i></b> (downy mildew)
This tomato leaflet has two fairly characteristic blight spots that are at different stages of development. Note that they first take on a pale green, livid hue, and gradually become necrotic thereafter. <i>Phytophthora infestans</i> (Mildew)
No sporulation is visible on these mildew spots observed on the upper side of this tomato leaflet. <i>Phytophthora infestans</i> (Mildew)
When the tomato leaflet is turned over, white sporulation is seen covering the weathered tissues around the periphery of the blight spots. <i>Phytophthora infestans</i> (Mildew)
Detail of <i><b>Phytophthora infestans</b></i> sporulation on the underside of a tomato leaflet. (mildew, late blight)
Extensive brown to blackish downy mildew lesion on tomato stem and petiole. <b><i>Phytophthora infestans</i></b> (downy mildew)
Mildew has recently set in on this green tomato fruit; it is only mottled and scalloped with brownish patterns. <i><b>Phytophthora infestans</b></i> (late blight)
Large poorly demarcated brown lesion on green fruit. This one is mottled and irregularly bumpy on the surface. <i><b>Phytophthora infestans</b></i> (downy mildew, late blight)
Several large necrotic spots of late blight affect some potato leaflets. <b><i>Phytophthora infestans</i></b> (downy mildew)
At the end of development, the lesions caused by <b><i>Phytophthora infestans</i></b> completely alter the leaflets, which become necrotic and dry up. (mildew)
Large spot of mildew on potato leaf. Wet, brown in color, it is surrounded by a livid, ill-defined margin of tissue. <b><i>Phytophthora infestans</i></b> (downy mildew)
This young spot of mildew observed on the underside of the leaf shows tissues of a livid tint and discreetly covered with a rather sparse white down. <b><i>Phytophthora infestans</i></b> (downy mildew)
The stem and young leaves of this potato tip have completely browned and become necrotic. <b><i>Phytophthora infestans</i></b> (downy mildew)
Brown to black canker lesion on the petiole of a potato leaf. <b><i>Phytophthora infestans</i></b> (downy mildew)
Binocular appearance of sporulation of <b><i>Phytophthora infestans</i></b> on affected tissues. (mildew)
Binocular detail of sporulation of <i>Phytophthora infestans</i> on affected tissues. (mildew)
Formation of a young sporangium, note the swellings sometimes present on the sporangiophores. <b><i>Phytophthora infestans</i></b> (downy mildew)
Several young sporangiophores with swellings are developing. (<i>Phytophthora infestans</i>) (downy mildew)
Formation of a young sporangium, note the swellings present on the sporangiophores. <b><i>Phytophthora infestans</i></b> (downy mildew)
Morphological variability of sporangia of <b><i>Phytophthora infestans</i></b> observed under a light microscope. (mildew)
Appearance of a fertilized oogonia of <i>Phytophthora infestans</i>. (mildew).