*3.2.2.1 Root rot disease of* E. pellita

Root rot disease infecting *E. pellita* in this study was observed to be very detrimental and trees dying in patches. The first signs typical of root rot disease attacked *New and Emerging Disease Threats to Forest Plantations in Sarawak Borneo, Malaysia DOI: http://dx.doi.org/10.5772/intechopen.107027*

#### **Figure 4.**

*Root rot disease of* Acacia mangium*; (a) 10-year-old trees with severe defoliation and open gaps are the most advanced symptoms of the disease; (b) Ganoderma fruiting body on infected trees; (c) red-coloured leathery rhizomorphs with blackish exudates on infected roots; (d)whitish mycelium on the under bark; (e) Brown root rot caused by the pathogen* P. noxious *with soft roots, fibrous and totally rotten and sand like soil (arrow adhering to the rhizomorphs).*

were yellowing of the foliar, and falling with twigs and branches die. The whole crown seems to be burnt-like (**Figure 6a**) and subsequently, the tree died with the tree became bare. The base of the stem and roots appeared rotten, and discolouration of bark stem was observed with fine white threads typical mottled pattern of mycelia growth below the bark (**Figure 6b**). Fruit body body's shape is like a fan, semicircular, hard and woody and the bottom surface is white; the upper middle is dark brown and measured around 50 cm was seen growing on the stem's base. The roots were then uprooted revealing red leathery rhizomorph covering the root system. Following the symptoms observed especially the characteristic of the fruiting found on the tree, the pathogen was identified as *G. philippii* [9].

**Figure 5.**

Erythricium salmonicolor *pink disease in* a.mangium*. (a)* E. salmonicolor *'cobweb' stage of infection.; (b)* E. salmonicolor *'pustule stage; (c) incrustation pink cobweb-like colonies on upper stems; (d) patches of tree death caused by the pink disease pathogen* E. salmonicolor*.*
