*2.2.1.2 Symptoms of yellow leaf in areca nut*

This disease was discovered as an investment of a Micoplasm-like Organism (MLO) attack. Symptoms are marked by yellowing of the leaf tips and as many as 2-3 strands

**Figure 1.** *Fruit rot on the areca nut [11].*

#### *Plant Diseases of Areca Nut DOI: http://dx.doi.org/10.5772/intechopen.107504*

of branching. Signs of necrosis in the form of brown parallel lines on the leaves, then yellowing extends along the leaf blade and the tips of the leaves dry up. At an advanced stage, the leaves turn yellow and fall off the stem. Symptoms can also be observed at the tips of the roots which gradually turn black. This infection in mature leaves causes the functional leaf cross-sectional area for photosynthesis to decrease (**Figure 2**).

#### *2.2.1.3 Symptoms of foot rot in areca nut*

This disease is caused by infection with the fungus *Ganoderma lucidum*. The leaves turn yellow and eventually fall. The stem becomes brittle due to strong winds, and the color of the base of the stem shows a change to brown and secretes a dark liquid. Mushroom hood-shaped fruit grows at the base of the stem, changes in color at the roots and the condition of the roots is drier than before. When the infected stem is cut longitudinally, a brown discoloration can be seen along one meter of the height of the stem from the ground (**Figure 3**).

**Figure 2.** *Symptoms of yellow leaf disease [11].*

**Figure 3.** *(a) the hood of* Ganoderma lucidum *grows at the base of the stem, (b) disease symptoms on the canopy tree [12].*
