Why Are My Banana Plant Leaves Turning Black?

Black streak disease causes unsightly black leaves on banana plants.

In tropical areas around the world, the common fungal disease banana black streak causes the banana plant to develop blackened fronds. If you live where rainfall amounts are heavy, your bananas are more likely to contract it.

Symptoms

The first sign is the development of lesions on leaves, which often begins with yellow flecks forming on the undersides. Later, they grow into narrow red to brown streaks. The streaks continue growing until they become long and black, often causing yellowing of leaf tissue that surrounds the streaks.

Effects

If left untreated, black streak disease causes all of the plant's leaves to turn black. They may also appear to be soaked with water. All leaves of your banana plant can die and forming fruit can ripen before it is full size.

Prevention and Control

Do not plant bananas in holes or depressions where drainage is poor. Avoid planting bananas in soil that is heavy clay. Some varieties of banana, such as the Cavendish and dwarf Brazilian, are resistant to this disease. Spray your banana plants with an approved fungicide or petroleum distillate twice each month throughout the year to prevent black streak disease.

References

• University of Hawaii: Black Leaf Streak of Banana