There is a great entry risk in Brazil of tropical race 4 of Fusarium, the fungus causing Panama disease. Also called TR4 (Tropical Race 4), it affects most varieties of banana grown in culture in the country. Restricted to South Asia in the past, where its rapid and aggressive spread has caused severe losses in countries like the Philippines, Taiwan, Indonesia and China, the TR4 was recently detected in plantations in Africa. If this race comes to banana plantations in the Americas, experts say that the days of the Cavendish variety, which includes Dwarf Banana, may be about to end. According to these scientists, its arrival in the Americas is a matter of time. There are now at least 50 varieties susceptible to TR4, which converts this pathogen to a serious threat to world banana crop. In early April, the United Nations Food and Agriculture Organization (FAO) issued a warning about the return of Panama disease. According to the entity, the TR4 can cause losses of $ 5 billion per year. An already seen scenario From the 1970s, Brazilian people saw virtually disappearing from their table one of their favorite bananas, the Apple type. Consumption and marketing of this banana almost came to an end due to Panama disease, specifically the race 1 of the fungus causing this disease (Fusarium oxysporum f. sp. Cubense). The same scenario occurred with the Gros Michel variety in most producing areas of the world. Since then, the subgroup Cavendish varieties, resistant to race 1, and one of the major for exportation nowadays, were introduced. Currently, there is concern this situation repeats with Cavendish and the main cultivars of the internal market, Lady's Finger and Apple. Genetic breeding to resist quarantine pests of high socioeconomic impact should be preventive, and Embrapa Cassava & Tropical Fruits (Cruz das Almas, BA) has experience in the case of Black sigatoka, another banana disease that was found in Northern Brazil in 1998. The cultivars developed by Embrapa resistant to this disease, previously unknown in Brazil, were made available to farmers. "It was salvation for those producers because it was a new disease, we had no technology and control products. Also, conditions in the North were totally favorable for disease development," says Edson Perito Amorim, leader of the Banana Breeding Program of Embrapa. Prevention as the way For the study of TR4, Embrapa has partnerships with research institutions from countries where the disease is already present, such as the University of Queensland in Australia, and the Academy of Science of Guangdong, in China, or places that can work with pathogen without risk, as the University of Wageningen, in the Netherlands. With this partnership, the work to develop a specific method of diagnosis for TR4 and methodologies validation for selection of resistant materials have been completed. In partnership with the Center for Nuclear Energy in Agriculture of the University of São Paulo (CENA / USP), some of the genes for disease resistance were identified. This discovery opens up prospects for obtaining resistant varieties. "In our germplasm collection, some materials have been identified as resistant in other countries. We are doing cross breeding for two years already, so it is possible that we already have solutions", says Amorim. He is emphatic when saying that there is no breeding program in the world doing what Embrapa does: developing cultivars resistant to Panama disease by cross breeding. "That is why we have the best condition to seek the solution via genetic control of these diseases", says the researcher. Lines of action The work results of Miguel Dita, a researcher form Embrapa Cassava & Tropical Fruits, revealed that the most consumed varieties in the country are highly susceptible to TR4. "We tested varieties in greenhouses in the Netherlands to understand the process of plant-pathogen interaction that provided information on how the plant reacts to TR4. Results put Lady's Finger and Apple (which account for 70% of the domestic market) as susceptible. These data were important to have the confirmation of the risk TR4 represents to Brazil", he explains. In Bioversity International, where Dita worked the last three years, actions with TR4 were also conducted. One of them was the development of a contingency/holding plan for a possible outbreak of the fungus. The objective is to provide countries with information about the disease to facilitate detection of the incursion of the pathogen and the adoption of measures to contain or confine the pathogen and prevent its spread." Some countries in Latin America and the Caribbean have already begun the process of phytosanitary surveillance and are taking action based on this plan, which is a basic tool for detecting disease outbreaks", says Dita. The plan is open to everyone and should also be implemented in Brazil. In another line of action, a project funded by the Marketplace platform, which leaders are Bioversity International and Embrapa, conducts research on soil management in Costa Rica and Nicaragua together with partners from these countries. Fernando Haddad, plant pathologist at Embrapa Cassava & Tropical Fruits, explains that even with a material resistant to the pathogen, the population in the soil must be managed to increase the durability of resistance. It is noteworthy that Embrapa has already released materials resistant to the race 1 that occurs in Brazil as 'BRS Platina' (Lady's Finger type) and 'BRS Princesa' (Apple type). "We need to verify what is the behavior of these cultivars against TR4", Haddad adds. Concern of the banana sector There is considerable concern in the banana sector in relation to TR4, because Panama disease has no control, unlike sigatokas and other diseases. "If the disease is present in the area and the variety is susceptible, there is potential risk of 100 % loss of production . And the concern is great because we are talking about a disease that attacks a commodity, the Cavendish variety. Every exported banana to Europe and the United States is Cavendish", contextualizes the researcher. The fungus can go by different routes: contaminated soil stuck on shoes, tools, banana plantlets (obviously healthy but infected) and ornamental plants, which can also be a host. "It is very important that the quarantine measures at ports and airports and border points are restricted accordingly", says Haddad. The plant pathologist says the researches already developed by Embrapa over existing races in Brazil, both in the area of genetic breeding and in management of the disease, are a benchmark for controlling a possible outbreak of TR4 in the country. Today, Embrapa already monitors the existing pathogen populations in Brazil, which will help in the selection and recommendation of varieties and even a timely detection of an outbreak of TR4. Luis Pérez, a researcher at the Research Institute of Plant Protection (Inisav), in Cuba, a partner of Embrapa in research related to TR4, stresses that the entry of the new breed in the Americas can be "disastrous" for the banana industry and also for the food security: "This race is very harmful to Cavendish and other clones susceptible to races 1 and 2. Among the major exporters in the world, many countries are in Latin America, where the banana export is a major component of nation's gross domestic product. The fungus can also infect the clones that now occupy 80% of world's production." TR4's condition in the world The disease is present in Australia, Philippines, Malaysia, Indonesia, Taiwan, China, Oman, Jordan and has recently been reported in Africa (Mozambique). Miguel Dita says there is no exact data on the number of affected areas around the globe, but in Indonesia, for instance, in just three years (2000-2003), the planted area in West Sumatra dropped from 1400 hectares to 715 hectares. "In China, there are already over 40 thousand hectares affected. In the case of Taiwan, the exportation to the Japanese market fell exponentially from 2000 to 2008, from 350 million to 50 million boxes", he says. These areas are doomed for the cultivation of banana, since the fungus is an inhabitant of the soil and can survive even in the absence of banana for more than 30 years.