De voetziekte van Gerbera, veroorzaakt door Fusarium oxysporum Schlecht

Gerbera jamesonii Hook hybr. is grown under glass in the Netherlands for the sake of its valuable flowers; cultivation is difficult, as many of the plants die. The short stem, which bears a rosette of leaves, becomes discoloured, blackens and putrefies, while the leaves and flowers wither. Several fungi have been isolated from the rotting stems — mostlyFusarium oxysporum (Schlecht.) em.Sn. & Hans.,Pythium de Baryanum Hesse andGliocladium penicillioides Cda.-and experiments have been carried out to test the effect of these fungi on the plants. Three beds were planted with healthy Gerbera plants and the soil of each bed was then infected with one of the fungi. After a few weeks many plants growing on the bed infected with Fusarium became diseased, while those in the other beds remained healthy. The Fusarium was re-isolated from the diseased plants, so it was concluded that this fungus was the cause or one of the causes of the footrot of Gerbera. The disease can be controlled by soil sterilization and by surrounding the base of the stems with a well-aerated, porous and fastdrying substance such as gravel or vermiculite.