black sigatoka

Symptoms

Dark brown to black streaks on banana leaves expanding into elongate dark blotches with grey centers, severe defoliation killing entire plants within 1-2 seasons, bunches fail to fill properly + ripen prematurely with poor quality, complete crop loss in unmanaged plantings.

Easily confused with

• Banana streak disease

  How to tell them apart: Black Sigatoka (Mycosphaerella fijiensis) and Banana streak virus both produce dark streaks running parallel to the veins on the banana leaf lamina, but the cause differs. Mycosphaerella fijiensis starts as tiny reddish-brown specks that elongate into narrow rust-brown to black necrotic streaks, which enlarge into spindle-shaped lesions with a pale grey dead centre and a yellow halo; in humid weather the underside shows dark spore structures. Banana streak virus produces yellow-to-chlorotic streaks first that may later turn brown, often as continuous broken lines along the veins together with leaf distortion, vein clearing or back-throw, and stunting, but without the spindle lesions, grey dead centres or sporulation of the fungus. The fungal lesions are clustered and progressive from the leaf tip and margin; the viral streaks are scattered and systemic across young leaves.