The fungus can be spread in contaminated soil, so if the disease is suspected, be careful not to spread soil from around the affected plants on tools or muddy boots.
Weed control is important because some weeds are hosts, and in some cases they not show any visible signs of infection.
Where the disease is confirmed, taking care not to spread potentially infected soil around, remove the infected plant with as much root system as possible and destroy. Consider grassing over the area for at least fifteen years, or plant a resistant replacement.
Heavy watering and application of ammonium-based fertilisers (nitrogenous) may stimulate the production of new conducting tissue in woody plants and help them recover, but this does not guarantee that re-infection will not occur in future years. To do this, apply a nitrogenous fertiliser to the root spread; use sulphate of ammonia at 25g per sq m (1oz per sq yd), or urea at 50g per sq m (2oz per sq yd) once or twice during the remainder of the growing season. The fertiliser should be applied to the soil surface and then immediately worked (e.g. with a hoe) or watered into the soil.
Avoid replanting with the plants listed above as they are susceptible, especially Acer. Resistant plants include: Betula, Cercidiphyllum, Crataegus, Fagus, Gleditsia, Liquidambar, Morus, Platanus, Salix. Conifers are effectively immune.
See the download for a more complete list of susceptible and resistant plants.
Verticillium wilt – resistant and susceptible plants (Adobe Acrobat pdf)
There are no chemicals available to treat verticillium wilt.