The fructification of Hymenochaete noxia commonly known as Brown Root Disease is much less conspicuous than that of Fomes, and is also comparatively rare. When present it takes the form of a thin brown crust adhering to the base of the trunk. The surface of the crust is velvety, being covered with almost microscopical bristles. The disease is not confined to Hevea, but is also found on Castilloa, tea, cacao, camphor, coca and the shade tree Erythrina lithosperma (dadap) in Ceylon ; on Funtumia on the Gold Coast and on coffee in Java. The majority of cases affecting Hevea in Ceylon have occurred where old cacao has been cleared in order to plant rubber. Unlike Fomes, the fungus does not appear to travel independently through the soil, but is -only transmitted where the roots are in contact with other diseased roots or with dead wood upon which the fungus is growing. In order to prevent the appearance of the disease, the stumps of cacao which have been cut down in order to make way for rubber should be carefully extracted. Hevea trees killed by the fungus should be cut down and the roots dug up and burnt. The soil which the roots of the dead tree occupied should be dug over and quicklime forked in, but the elaborate precautions recommended in the case of Fomes do not appear to be necessary, as the fungus seldom spreads after the source of infection has been removed.
On the other hand, if Sphaerostilbe makes its appearance, the treatment recommended for Fomes should be carefully carried out, since this fungus, too, is able to spread through the soil to adjacent trees by means of a free-growing mycelium.