The banana plant (Musa) is an herbaceous, fruiting plant that belongs to the Musaceae family. Native to tropical Asia, the tall, sturdy banana plant is often referred to as a tree. Banana trees are primarily planted for their healthy banana fruits. These tropical plants are susceptible to a variety of potentially serious diseases.
Black Sigatoka is a fungal disease (Mycosphaerella fijiensis) that thrives in the heat and humidity of the tropics. This leaf spot disease causes the formation of dark spots, which gradually enlarge and emerge until the affected leaf turns brown or yellow. This disease drastically reduces a banana tree's fruit production. Removing the affected leaves and pruning foliage for better air circulation can reduce the risk of black Sigatoka infections.
Panama disease of bananas is a classic vascular wilt disease caused by a fungus (Fusarium oxysporum). The fungal pathogens enter the banana tree through the xylem, and then use the water stream to spread the fungal spores throughout the entire plant. These spores lodge into the vessel walls and block the water flow, causing banana leaves to wilt and die. Panama disease often kills entire banana trees. The fungal pathogens can survive in the soil for almost 20 years. This disease is extremely difficult to control, and almost destroyed Central America's banana production back in the 1940s and 1950s.
Banana Bract Mosaic Virus
The banana bract mosaic virus (BBrMV) is a disease spread by several species of aphids. This banana tree disease causes a brown or dark red mosaic pattern to form on the flower bracts. Red or green streaks or lesions sometimes appear on the new leaves, while chlorotic streaks often form on the bunch stems. Banana bract mosaic virus can cause significant fruit loss on affected trees. This banana plant disease is difficult to control because the symptoms are frequently inconspicuous. Preventative measures include using virus-free stock and planting materials.
Banana Bunchy Top Virus
Banana bunchy top virus (BBTV) is a serious banana tree disease spread by banana aphids (Pentalonia nigronervosa). This disease causes dark green streaks or spots to form on newly emerging banana leaves. Infected banana trees produce narrow, wavy leaves with yellow margins. The affected leaves tend to bunch up at the top of the banana plant, which is how this disease earned its name. Affected trees typically don't bear fruit. Those that produce fruit generally bear twisted or distorted bananas. Banana bunchy top virus is extremely difficult to control once it is established. Prevention includes controlling the banana aphids with insecticidal soap or pesticides.
Moko disease of banana is caused by a soilborne bacterium (Ralstonia solanacearum). The pathogens enter the banana tree through root wounds, and quickly grow and spread throughout the entire plant. The primary sign of moko disease is wilting and breaking leaves. All leaves on an infected banana tree eventually dry out. The fruit quits growing once the tree becomes infected. The banana fruit typically look deformed and shriveled. Moko disease of banana spreads easily through infested soil, runoff water and insects.