Laboratory in Bahia helps producers export Tahiti lemon to the European Union

The Department of Plant Health of the Ministry of Agriculture and Livestock (Mapa) recently recognized the Phytopathology Laboratory of Embrapa Cassava and Fruticulture (BA) as capable of issuing a report for citrus wart disease, a fungal disease that limits the shipment of Tahiti acid lime fruits (better known as Tahiti lemon) to the European Union (EU) due to the phytosanitary restriction for Elsinoë spp., a pest considered quarantine, that is, non-existent, on that continent. Although Bahia does not record the occurrence of the disease, as do some other Brazilian regions, the absence of a report certifying the health of the batches makes exporting to the EU difficult.

Around 200 samples from producers in the states of Bahia (especially the Cruz das Almas region), Sergipe and Minas Gerais have already benefited, since the beginning of April, from the proximity of the laboratory, which issues the reports in the period from one to ten days, depending on demand and the presence or absence of symptoms in the fruits. Bahia is the fourth largest Brazilian lemon producing state, behind only São Paulo, Minas Gerais and Pará, and is responsible for exporting fruits totaling US$34 million in 2023.

caused by fungus Elsinoë, wart disease affects leaves, fruits and shoots in citrus-producing areas around the world. It has great economic importance because the appearance of the peel, with prominent lesions and thick crusts, drastically reduces the commercialization of the fruits, especially those destined for export. Some symptoms of wart are similar to those of citrus canker, a bacterial disease caused by Xanthomonas citri subsp. citri, also not present in the European Union, but present in some Brazilian states. Bahia has been a citrus canker-free area since 2017.

According to researcher and phytopathologist Francisco Laranjeira, general manager of Embrapa Mandioca e Fruticultura (BA), from a biological point of view, the similarities with citrus canker only occur in the appearance of the fruits, which can cause confusion for laypeople. “Wart is a fungus; Cancer is caused by bacteria. The cancer 'passes' from one fruit to another, as the bacteria can remain in the box and even on the hand of the person who picks up the fruit. A fruit infected with wart does not infect a healthy fruit, even if they are in the same box. It can even transmit spores, but there will be no infection because warts only infect immature tissues,” he says.

Real Time

According to information from the Brazilian Agriculture Observatory, Brazil received, in 2023, US$ 139,3 million from the sale of acid lime fruits, according to data from the banks of the Agribusiness Foreign Trade Statistics System (AgroStat) and of the Integrated Foreign Trade System (Siscomex). According to the Brazilian Association of Fruit and Derivatives Exporters (Abrafrutas), together, lemons and limes are the fourth fruit exported by the country, behind mangos, melons and grapes.

Agricultural tax auditor Caio César Simão, head of Mapa's Special Export Programs Division, confirms that, in relation to lime exports to the European Union, the organization's main concern has always been citrus canker. “But, from 2021 onwards, they started to intercept many Brazilian shipments with warts, which is a quarantine pest, that is, absent there. We, Brazilian researchers, inspectors and producers, have always had great difficulty finding these symptoms of wart because it is not a problem in acid lime. So, we started monitoring the fields, a greater control of ours, with support from Embrapa, with the aim of facilitating and maintaining exports”, he explains.

From January to May, 60 containers of acid lime from Brazil were returned by European Union customs. “This may not be so harmful for the individual producer, but it is very bad for Brazil. On other occasions, the citrus markets in Argentina and South Africa have already been closed. Due to a similar problem, early blight, our export of orange fruits to Europe also ended. Today we only export juice”, recalls Simão.

In the specific case of Bahia, according to data from Mapa, the rejection of cargo originating in the state due to the presence of Elsinoë spp. have increased in recent years, from three in 2022, to seven in 2023 and ten by June 2024. “The increase in interceptions does not mean an increase in the problem in Bahia, but greater rigor in Europe in relation to detecting the pest”, observes the researcher.

The report for warts then became mandatory. “It is a measure that Mapa adopted to guarantee the compliance of shipments and was not a requirement of the European Union. Europe doesn't have warts and doesn't want to have one. So, we need to carry out monitoring so that the producer can improve practices, selection and sampling”, explains the ministry representative.

Inspection and audit

Citrus canker has been one of the major concerns of the State Agricultural Defense Agency of Bahia (Adab), since 2005, when Ordinance No. 119 was established, which provides for standards applicable to the production, transit and trade of seedlings, rootstocks , buds and fruits of citrus species in the state of Bahia.

The objective of the ordinance is to prevent the introduction of pests, such as citrus canker, wart, sudden citrus death (MSC), citrus black spot and huanglongbing (HLB or greening), which would be major threats to the Bahian citrus park. As a result of producers complying with the ordinance and the agency's inspection, the state is considered a free area for citrus canker, which shows a competitive advantage in relation to other states, including São Paulo, which is the largest Brazilian producer.

State agricultural inspector Suely Xavier de Brito Silva, coordinator of the Adab Citrus Phytosanitary Project, highlights the importance of the state ordinance. “It prohibits the processing and reprocessing of fruits that have not been produced in Bahia. This is a safety measure so that they do not enter fruits with symptoms of pests that could establish themselves here”, she warns.

As for wart in acid lime, she states that her team had never observed any type of lesion on fruit: “It has never been a problem because we have no record of economic damage from this pest to citrus growing in the world, and not just in Brazil. When we have a pest that does not cause economic damage, we can have control strategies and coexistence strategies.”

Regarding the analyzes carried out by the Embrapa laboratory, Suely Silva says that it was a recommendation from Adab to Mapa. “We thought about the number of family farmers who would benefit from this process, mainly from Bahia.”

How the analysis happens

The laboratory report issued on behalf of the production unit (UP), indicating the presence or absence of the pest, is valid for 30 days and must be presented by the producer to Mapa's International Agricultural Surveillance (Vigiagro), at the sea port, for the purposes of export certification.

According to the Mapa letter, each sample must contain at least 20 fruits. 2% of the trees in each UP must be sampled, collecting at least one fruit with bark lesions per tree sampled. The laboratory report issued must explicitly state the number of the UP from which the sample was taken.

The producer is responsible for collecting and transporting samples to the laboratory. “After receiving the sample, we register and begin the evaluation. All fruits are evaluated under a magnifying glass to check the presence of wart symptoms. If typical symptoms are identified, we take slides of the affected part of the fruit and analyze them under an optical microscope to see if we can find signs of the fungus, which are the hyaline, elongated spores [conidia]. If the structures of the fungus are identified and validated based on morphological characteristics, the sample is considered positive”, explains agricultural engineer Leandro de Souza Rocha, supervisor of the Laboratory Management Sector at Embrapa Mandioca and Fruticulture and responsible for the Phytopathology Laboratory. .

Producers served

For agricultural engineer and citrus consultant based in Recôncavo Baiano, Gabriel Pedreira da Paixão, carrying out the analyzes by Embrapa greatly helped the region's Tahiti acid lime production chain. “It benefited producers, technical managers and traders in the sector in meeting Mapa’s requirements. The first point is the ease and reduction in the cost of transporting samples to accredited laboratories. Previously, they had to be sent to other states, such as Rio Grande do Sul, São Paulo and Rio de Janeiro”, explains Paixão, who is also a technician responsible for issuing the Phytosanitary Certificate of Origin (CFO) and the Consolidated Certificate of Origin ( CFOC).

The cost of the procedure is also an advantage. “It is about four times smaller than other laboratories due to the morphological analysis method carried out at Embrapa being faster, using fewer resources and being as efficient as the PCR method [molecular biology technique that amplifies a specific region of DNA]”, highlights.

Technologies to prevent warts

Laranjeira warns that some actions taken in the field can prevent fruit contamination by wart disease: spraying, at the right time, with suitable products registered on the Map; monitoring the area to remove material with symptoms and correct disposal; and guidance to the harvest team to separate suspicious fruits. In the packing house, the greatest care must be taken with the pre-selection of the fruits. “At all these stages, producers can count on the transfer of technologies from Embrapa, such as cultural treatments, the production system and, even, the training of field assistants and technicians, such as pest control workers. There is no variety resistant to wart disease, but all these technologies are useful to have good production with a lower risk of the disease occurring”, informs the phytopathologist.

On July 11, in a meeting with representatives from Abrafrutas and producers and exporters of Tahiti acid lime, it was decided that Embrapa Mandioca e Fruticultura will offer technical support to improve the management of the disease in the field, in order to reduce fruit infection. by the fungus. “We will also improve laboratory tests for detecting the fungus so that they are more specific for species considered quarantined by the European Union. Together with Abrafrutas, we were willing to contribute technically to Mapa to improve the protocols applied for the export of Tahiti sour lime”, adds researcher Eduardo Chumbinho de Andrade, deputy head of Research and Development at the Embrapa Research Center.

The disease

Wart attacks sour oranges, sweet oranges, tangerines, tangors and sour limes and affects the fruits during the first three months of life. Lesions on ripe fruit will be greater the sooner the fruit is attacked. In addition to depreciating its commercial value for the fresh fruit market, the lesions that the fungus produces on the fruit skin also serve as a hiding place for the leprosy mite, making it difficult to control.

When wart appears in seedbeds and nurseries, affecting the main rootstocks used in citrus farming, the attack is directed, preferentially, at young tissues, causing raised and rough lesions on leaves and young branches. The initial symptoms on the leaves, which are still transparent, are small, shiny, watery spots.

Control must begin, preventively, when the fruits are just beginning to form, as the fruits are susceptible up to 12 weeks after the petals fall.