عزل و تحديد الفطر Colletotrichum coccodes كمسبب لمرض النقطة السوداء على البطاطا البطاطس في سورية

Abstract EN

Black dot (Anthracnose) is an important disease affecting potato in many regions worldwide, causing significant losses in yield.

The disease was recorded recently (2006) for the first time on potato in Syria, in some potato fields at Hama and Idleb, on Panella and Sponta varieties.

The fungal pathogen was isolated from roots, stems and tubers of infected plants, and identified as Colletotrichum coccodes (Wallr) Hughes.

The pathogenicity test of the fungus was studied in glasshouse under artificial inoculation of the soil, using 45-55 mm potato tubers Panella variety, Elite seeds.

Symptoms were observed after 65-70 days when leaf wilting and chlorosis, followed by necrosis and death of infected plants was observed.

Black dots were observed on the lower stem of infected plants, where the intensity of acervuli and microsclerotia was proportional with the severity of infection.

The disease was destructive to both stems and roots, but without vascular discoloration symptoms.

However, a gray-brown patches were observed on the surface of affected tubers, representing acervuli and sclerotia.

The size of patches on tubers expanded and fused with each other under unfavorable storage conditions, which lead finally to tuber skin wrinkling which reduced the market value of the tubers.