Banana leaf speckle (Mycosphaerella musae)

Banana leaf speckle is a common general name given to several species of fungi that are capable of reflecting diffused circular or irregular blotches on banana leaves that come in many colors such as grey, brown, and black. This fungal disease can be a problem from October to May. Infection occurs during wet periods and when there is water on the leaves for long periods.

The diseases cause the early decease of the surface of infected banana leaves resulting in the reduction of total leaf area for photosynthesis process.

Symptoms of leaf speckle first appear as pale-brownish spots, like pencil marks, 0.5 x 1.5 mm. These spots are easily distinguished by transmitted light and can be seen 3-4 weeks after the youngest leaf unfurls. The spots elongate to streaks which increase in size, becoming lesions about 15 x 30 mm.

If the disease becomes severe, the leaves will die and drop off and small bunches with early and uneven ripening can result.

In general, speckle diseases are only of minor importance, and are unlikely to reduce yield. The exception is Mycosphaerella musae, which can be serious in commercial plantings if not controlled, resulting in loss of leaves, and poor fruit yield.
Banana leaf speckle (Mycosphaerella musae)