Complex sentence: During the 1950s, Panama disease wiped out (everywhere except Asia) the Gros Michel banana, the dominant cultivar of bananas, inflicting enormous costs and forcing producers to switch to other, disease-resistant cultivars.
Split into simpler sentences: During the 1950s, Panama disease wiped out the Gros Michel banana everywhere, except in Asia. The Gros Michel banana was the dominant cultivar of bananas, and the blight inflicted enormous costs and forced producers to switch to other, disease-resistant cultivars.