Biologische Bekämpfung von Botrytis cinerea mit Ulocladium atrum in Reben und Cyclamen

Botrytis cinerea causes world-wide yield loss in many crops and fungicide resistant strains impede the control. Beside chemical control, antagonistic bacteria and fungi were used for biological control. The saprophytic hyphomycet Ulocladium atrum has shown an antagonistic effect against B. cinerea and competition seems to be the mode of action. In field experiments with grapevine the antagonistic effect was proved in the last two years. Under controlled conditions the antagonist was insensitive against most fungicides used in conventional disease control. This effect was also shown under field conditions, therefore the antagonist can be integrated easily in existing crop protection systems. The results of field experiments with grapevine at Marienthal in 1997, and at Geisenheim and at Marienthal in 1998 confirmed the antagonistic effect of U. atrum against grey mould. At both examined locations this effect could be observed in the two cultivars 'Muller Thurgau' and 'Riesling'. The antagonist was also effective in cyclamen. In various cropping systems rot of leaves and petioles caused by B. cinerea was significantly reduced. Only under extremely high disease pressure, no effect of U. atrum or fungicides was found.