Root pathogens are not fully adapted to life outside a host and cannot persist indefinitely in soil. It is possible to apply effective, but not absolute, control of root pathogens by removal of live and dead host material. This involves as complete as possible removal of all roots of both tea and shade plants. and necessitates culling of apparently healthy bushes as well those obviously infected. In practice, it is not possible to remove all infected host material, but the planting of non-host, such as grasses for a period of at least 2 years reduces the amount of infective material in the soil and also improves the nutritional and physical condition. The incidence of root disease usually increases following felling of shade trees, but this may be controlled by ring barking before felling.