Which strain of Panama disease currently threatens the global Cavendish banana crop?

The strain of Panama disease currently threatening the global Cavendish banana crop is Tropical Race 4, usually abbreviated TR4.

Panama disease, also called Fusarium wilt, is caused by soil-borne Fusarium fungi. Earlier outbreaks devastated Gros Michel bananas, once the dominant export variety, but Cavendish bananas resisted that particular strain. TR4 is different: it can infect Cavendish cultivars and has spread through soil, water, farm equipment, vehicles and infected planting material.

The pathogen can persist in soil for years, making eradication extremely difficult once a plantation is contaminated. Biosecurity measures therefore focus on quarantine, sanitation and preventing the movement of soil and plant material. TR4 should not be confused with Race 1, which destroyed much of the Gros Michel industry, or Race 2, which primarily affects certain cooking bananas.

The broader scientific name is Fusarium oxysporum f. sp. cubense, a group that contains several races and lineages. TR4 is the form associated with the modern Cavendish crisis, not a separate disease unrelated to Panama disease.