Sphaceloma ampelinum of Grape Scab in thailand

Abstract

In Thailand in 1990, s. ampleinum de Bary was first isolated and identified from fruit lesion of grape scab disease (local name e-Bub). The disease occurred in chiang Rai Nakhon Prathom Nakhon Ratchsima Ratchabrui Lampang Samutsakhon and Phichit provinces.
The symptomatology of the disease and morphology of the fungus were studied in details in 1991 - 1992. The fungus caused severe damages on grape growing shoots and fruits. Dark brown cankerlike irregular spots appeared between and on large veins of leaves and on petioles caused distortion. Drizzling rain and abundant dew favoured the disease occurrence.
Koch's postulates were carried out in greenhouse on grape marcotts variety White malaga growing whith 2-3 young shoots and 2 months old detached fruits were inoculated with conidial suspension of s. ampelinum. Typical disease symptoms appeared on yound shoots and fruits after 10-20 days under greenhouse and laboratory conditions. The fungus was successfully reisolated from the inoculated lesions and thus confirmed that it was indeed the cousal organism of grape scab in Thailand.