Exotic plant pests - black Sigatoka 

Worldwide, black Sigatoka is one of the most devastating leaf diseases of bananas. It occurs in Papua New Guinea and on several islands in Torres Strait. It has also occurred at five locations on Cape York Peninsula (i.e. Bamaga, Pascoe River, Bloomfield River, Weipa and Daintree) since 1983.

In April 2001 it was found for the first time in a commercial production area near Tully in north Queensland, but has since been eradicated. 

Cause of black Sigatoka

Black Sigatoka is a fungus called Mycosphaerella fijiensis. It is spread by spores carried in the wind. Black Sigatoka spores can infect all the banana plant including leaves, suckers used for planting as well as leaf litter which in turn can contaminate fruit shipments.

What does it look like?

Early lesions are reddish brown areas on the underside of the leaves. There is a similar fungus disease, yellow Sigatoka that causes yellowish green areas mostly on the upper leaf surfaces. These diseases are very difficult to tell apart and may even occur together on the same plant.

Heavy infection with black Sigatoka causes the infected tissue to turn  black, surrounded by yellow leaf tissue. The black parts gradually die off. In yellow Sigatoka the discolouration is more brown than black.

Black Sigatoka is a leaf disease of bananas.		Black Sigatoka.

Effects of black Sigatoka

Infected leaves die, reducing yield and making the fruit ripen prematurely. These effects cause economic hardship to growers.

Last reviewed 10 February 2005