All three diseases look similar, but Black Sigatoka poses the biggest threat. It afflicts a wide range of bananas, including the “Cavendish” variety. This is the sweet “dessert” banana enjoyed in most Western countries. Yellow Sigatoka is a milder disease. Eumusae leaf spot falls somewhere in between the two Sigatokas in terms of threat.
The fungi are closely related. So researchers at the University of California, Davis were puzzled about why they cause such different degrees of harm.
To find out, they worked with researchers at Wageningen University in the Netherlands. The team mapped out the complete set of genes, or genome, of all three fungi. Like other organisms, fungi will, over time, develop mutations — changes in their DNA. Some genetic tweaks could help the fungi survive. Such beneficial DNA changes would likely carry over to future generations.