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Late blight symptoms on potatoes

 

  • Organs attacked :

 

Leaves flowers
tubers stems

 

  • Symptoms
    • Pale green to brownish green spots on the leaflets at first wet. These spots are frequently surrounded by a livid, ill-defined tissue margin (Figures 1 and 2).
    • Large sectors of the leaf blade browning and becoming necrotic (figures 3 and 4)
    • Browning of the apices (figure 5) and brown cankered lesions on stems and petioles,  more or less extensive, and with an irregular outline (figure 6).
    • Diseased plants are distributed in clusters in the plots; When the conditions are favourable, the progression of the symptoms on the plants and in the culture is dazzling: leaves, twigs, even plants end up necrosing and drying out completely.
       
  • Signs : presence of a discreet and fleeting white down  on the underside of the leaf blade (figure 7); this is made up of the sporocystophores and sporocysts of P. infestans.

 

  • Production areas affected :
Reunion New Caledonia
Last change : 07/21/22
Phytophthora-Tomate3
Figure 1
Phytophthora-Tomate4
Figure 2
Phytophthora-Tomate1
Figure 3
Phytophthora-Tomate2
Figure 4
Phytophthora-Tomate6
Figure 5
Phytophthora-Tomate7
Figure 6
Phytophthora-Tomate5
Figure 7