verticilliose de la fraise

Symptômes

Les feuilles externes les plus âgées se flétrissent et s'aplatissent tandis que les feuilles internes restent dressées, aucune récupération nocturne, décoloration vasculaire du cœur à la coupe, les plantes meurent en 2-4 semaines, les stolons transmettent la maladie.

Souvent confondu avec

• phytophthora de la fraise

  Comment les distinguer: Phytophthora fragariae (red core / red stele) is a soilborne oomycete: above ground you see stunted, blue-green or wilting plants in wet, low-lying, poorly drained patches of the bed, with outer/older leaves turning red or yellow and collapsing while the plant dies back. The decisive sign is INSIDE the root: slice a young white feeder root or the main root lengthwise and you find a rusty red-to-brown discoloured central core (the stele) sharply contrasting with the surrounding healthy tissue, while the outer root cortex rots away. Roots look rat-tailed (side rootlets rotted off). Verticillium dahliae wilt produces a similar wilting, stunted plant, but symptoms appear in dry/warm conditions and are NOT tied to waterlogged spots; outer leaves wilt, dry brown at the margins between the veins and flatten to the ground in a collapsed rosette while the youngest central leaves stay erect and greenish. Cut the CROWN and leaf-stalk bases (not the root core): Verticillium shows brown-to-bluish vascular streaks/flecks in the crown and petiole tissue, with no clean red central stele in the roots. Both Phytophthora fragariae and Verticillium dahliae are common, EU-established soil diseases here; no notification is required for either. Use the red root core (P. fragariae) versus the crown/petiole vascular streaking (V. dahliae) simply to choose the right management, and manage them normally with good drainage, resistant varieties and clean planting stock.