Fusarium
Introduction
Fusarium oxysporum is a common soil-borne fungus. There are many strains of this species, some of which are highly specific to a limited host range. The disease can be a problem in cucumber, sweet pepper, tomato and various pot plants and cut flowers.
Life cycle
The fungus survives thanks to thick-walled resting spores, which can spread through water. The spores survive on the soil, greenhouse fittings and fixtures, organic material in the soil, and can also attach themselves to seeds. They remain capable of germinating for over a year, and can infect the plant through small injuries formed for example when young roots break through. The fungus can grow into the plant through the xylic gaps. In damaged roots, the fungus can form new chlamydospores.
Indicators of damage
Characteristic symptoms are wilting, rotten roots and brown vascular bundles. Fungal growth in the vascular bundles and toxins cause the wilting. The foot of the plant turns brown and splits. The fungal weft develops here, with spores that can result in reinfection. This weft can sometimes later also occur on stems and tendrils.
