Crops
Symptoms Didymella on Cucumber
- Organs attacked :
| Leaves | Fruits |
| rods | Collars |
- Symptoms :
- Oily to livid spots on leaves. Rather circular in shape, they expand as they evolve, take on a brown hue, become necrotic and dry out. Note that they are often located at the edge of the blade, and that a yellow halo sometimes surrounds them (figures 1 to 3).
- First moist and dark green lesions on stems (aerial parts -figure 4- and collar -figures 5 to 7-), gradually browning and becoming necrotic. Reddish-brown to black gummy exudates on these (Figures 7 and 8). These lesions often start from pruning wounds, grafting or senescent tissue present on the stem and cover large portions of stems.
- When the stem is girdled the plant can wilt and dry out (figure 9).
- Initially limited, moist and dark lesions on fruits (figures 10 to 13) starting from more or less senescent floral parts, at the level of the stylar zone, sometimes from micro wounds. Irregular in shape, they spread and gradually brown or even blacken; the flesh takes on a brown to blackish hue.
- Signs : relatively quickly forms tiny black globular structures on the altered tissues (figures 3 and 8): perithecia and pycnidia which produce ascospores and conidia respectively in large quantities, especially during wet periods.
- Possible confusion :
- >>> More pictures
- Production areas affected :
| Reunion | Guyana |
Figure 1
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Figure 4
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Figure 7
Figure 8
Figure 9