First report of Fusarium oxysporum f. sp. cubense tropical race 4 (VCG 01213/16) associated with Cavendish bananas in Laos

The popular Cavendish banana (Musa spp., AAA) constitutes about 45% of all bananas grown worldwide (Lescot, 2015). Mainland China is one of the leading producers of Cavendish bananas, and to satisfy local demand for the fruit, commercial production is expanding into neighbouring countries such as Laos, Myanmar and Vietnam. In Laos, local banana varieties such as "kuay nam" (Silk, AAB), "kuay hom" (local Cavendish, AAA) and "kuay klai" (Horn Plantain, AAB) are preferentially grown for food and income generation. The expansion of Cavendish production from China into Laos, therefore, presents significant risks to these varieties, such as the introduction of Fusarium oxysporum f. sp. cubense tropical race 4 (TR4; VCG 01213/16), a soil-borne fungus that causes severe epidemics and crop losses in Cavendish plantations in southern Chinese provinces. In November 2016, Laos Department of Agriculture staff reported wilting plants from Luang Namtha and Borkeo provinces. In February 2017, yellow leaf symptoms typical..