Occurrence of Fusarium oxysporum f. sp cubense Tropical Race 4 and Other Genotypes in Banana in South-Central Mindanao, Philippines

The fungal pathogen Fusarium oxysporum f. sp. cubehse Tropical Race 4 (Foc TR4) causing Fusarium wilt in banana is becoming a threat in the banana industry worldwide. It causes serious epidemics in some areas of Mindanao, Philippines, both in Cavendish and local varieties. Molecular detection of TR4 and phenotypic analysis of Foc isolates through vegetative compatibility grouping (VCG) test was done to determine Foc diversity in South -Central Mindanao, Philippines. Out of 75 representative isolates, 25 were Foc TR4 based on molecular detection. Twenty-two Foc TR4 were confirmed as VCG 01213/16 in VCG test with three isolates undetermined as they were not included in the analysis. The identified Foc TR4 isolates were collected from North Cotabato (9), South Cotabato (7), Saranggani (3), Davao del Sur (2) and General Santos City (4), isolated from Lakatan (12), Cavendish (11) and Latundan (2) varieties. This result indicates the rapid spread of the devastating pathogen in banana production areas of the above provinces both in backyard and plantation areas. Mitigating measures such as public awareness and implementation of integrated disease management are necessary to prevent further disease spread. Moreover, 14 isolates were identified as Genotype 8 and three were Genotype 9 from Latundan variety. Two isolates were placed under unknown VCG 1, and five under unknown VCG H which might represent novel Foc VCGs since members of each group were cross compatible but not compatible with any known VCGs tested. In addition, 13 isolates did not pair with known VCGs tested or with each other. Pathogenicity testing should be made to determine whether or not the above isolates are pathogenic or non-pathogenic endophytes which are also commonly found within Musa spp.