Studies on the pathogenesis, epidemiology and controllability of Mycosphaerella brassicicola (Duby) Lindau, the causal agent of ring spot disease of crucifers.
Zornbach, W.
Mitteilungen aus der Biologischen Bundesanstalt fur Land- und Forstwirtschaft Berlin-Dahlem Year: 1990 Issue: No. 262 Pages: 105 pp. Ref: 86 ref.
1990
บทคัดย่อ
In vitro studies showed M. brassicicola to produce 2 types of mycelium: black, slow growing and able to produce ascospores, and white, faster growing and presumably vegetative. The life cycle of the fungus on white cabbage was elucidated: it was completed in 5-6 weeks at 20 deg C and opt. RH. The pathogen was not found to be seed transmissible. Cotyledons of several Brassica spp. were successfully inoculated with mycelium. The pathogen had a wide host range, although white cabbage cultivars Carlton, Erdeno, Krautkaiser, Olympiade and Pluton were resistant. A study of the epidemiology of the disease in Schleswig-Holstein, Germany, showed that infections in cabbage originated from severely infected neighbouring rape crops. The complementary growing seasons of the 2 hosts enabled development of polycyclic epidemics. Ascospore release occurred at temp. more than or equal to 0 deg and RH >80% at 2 m above ground level. Postharvest losses on white cabbage were reduced by storage at 0 deg and 95% RH; a
t higher temp., treatment with thiabendazole gave protection against secondary infection by Botrytis cinerea. Triadimenol, tebuconazole and carbendazim inhibited in vitro growth of M. brassicicola; in vivo, tebuconazole gave the best control, but was in some instances phytotoxic.