Location: Tropical Crops and Germplasm Research
Project Number: 6090-21000-061-017-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2024
End Date: Oct 1, 2026
Objective:
1. Sample and identify which Fusarium oxysporum f. sp. cubense (Foc) races are present in banana and plantain fields throughout Puerto Rico. If Foc TR4 is not present, understanding the population structure of the other Foc races will help predict the impact of TR4 when it arrives.
2. Relate distribution of Foc races and Fusarium wilt (FW) symptoms to environmental metadata, including soil type, elevation and climate. 3) Relate distribution of Foc races and Fusarium wilt (FW) symptoms to biological metadata, especially the presence of other banana pests and diseases: sigatoka, nematodes and banana weevil (Cosompolites sordidus), when observed. Damage by other pests may make plants more susceptible to Foc and vice versa.
Bananas and plantains are the world’s most consumed fruit and one of the top ten staple foods. In the US they are grown in Hawaii, Florida, the Virgin Islands, Guam and Puerto Rico. Bananas and plantains represent important cash crops for many insular areas within the U.S. In 2014-15, plantain production in Puerto Rico had a farm-gate value of $72.4 million, whereas bananas had a farm-gate value of $29 million. Bananas and plantains are threatened worldwide by the fungal pathogen Fusarium oxysporum f. sp. cubense (Foc) (= F. odoratissiumum), the causal agent of ‘Fusarium wilt’ (FW, also called ‘Panama disease’). Bananas are clonally propagated with a few genotypes grown worldwide. Therefore, lack of diversity in commercial orchards makes these very susceptible to diseases. The most important banana for the local and export market is Cavendish is resistant to Foc Races 1 and 2 but highly susceptible to the more virulent Tropical Race 4 (TR4). Since Cavendish is the dominant banana cultivar in Puerto Rico, Hawaii, Guam and the USVI, all are highly vulnerable to Foc TR4. Surprisingly, there is no current effort to monitor fields for TR4 in Puerto Rico. The most recent disease survey was conducted in 2017, before TR4 had been detected in the Americas and before reliable methods for differentiating TR4 were available (Garcia et al., 2018). No mitigation/quarantine plan has been developed to minimize potential impact on cultivars used by growers if the disease were to be introduced into the island.
Approach:
Objective 1: Sample and identify which Fusarium oxysporum f. sp. cubense (Foc) races are present in banana and plantain fields throughout Puerto Rico.
A visual inspection for FW symptoms will be done on at least 20 large banana farms, including three major production areas in Puerto Rico. Culturing: When symptoms are found, Fusarium spp. will be isolated from root and stem tissue on standard culture media and identified by microscopy. Healthy control plants will be included. DNA sequencing: Partial sequences of three nuclear genes used to differentiate races of Foc will be generated with Sanger sequencing. Fusarium fungi will be identified to species and race by comparison to sequence databases.
