Rubber diseases may be classified according to parts they affect - leaf, tapping panel or root. Root diseases spread by root contact with a source of inoculum such as infected woody debris in the soil. The most important root disease is white root rot. The pathogen travels both internally and externally along the roots, which decay in the process, and eventually reaches the collar and tap root, whereupon the tree soon dies. A recent approach to white root disease control is to drench the soil around the tree with a fungicide. Research has demonstrated that applying the most effective fungicides as protectants for white root disease resulted in no infection compared with 95% infection in the untreated plots (Tan and Hashim, 1992)..