Municipality of Campaign, in Minas Gerais, receives task force against greening

With the aim of minimizing the damage caused by HLB/greening to citrus crops in the state, the Instituto Mineiro de Agropecuária (IMA), an agency linked to the Secretariat of Agriculture, Livestock and Supply (Seapa), develops a task force in the city of Campaign, in the south of Minas. IMA technicians go to properties to identify the disease and notify producers, giving a deadline for regularization. The action began this week and had the support of associations, unions and city hall.

The acronym HLB comes from the name of Chinese origin Huanglongbing, but the pest is also known as greening or yellowing, a disease that affects citrus and myrtle plants. Transmitted by a vector, a psyllid - a species of cicada measuring around three millimeters -, the bacteria attacks the plant's main vessels and, therefore, spreads very quickly, meaning pruning is not sufficient for the plant to survive. When attacked by HLB, the plant needs to be eradicated.

Because it is fatal and brings countless losses to the sector, IMA developed, at the end of 2023, a pilot project in the southern region of the state, where citrus production stands out. For this action, the institute brought together rural producers, city halls and bodies related to the subject, such as Emater and Epamig, and established ten goals, including encouraging producers to register with IMA. 

The result of this first stage was the regularization of more than thirty rural citrus producers in the region, who registered with IMA. This joint work did not even result in an infraction notice.

Registration with the IMA, in addition to being a legal requirement, allows the agency to monitor production in the state and, thus, be able to contain possible outbreaks of the disease. The state has some critical regions, those that produce tangerines, the crop most affected by the pest. 

Among the areas with the highest incidence of HLB are the Triângulo Mineiro, the South of Minas, Alto Paranaíba, Zona da Mata and the Central region of the state. The city of Belo Vale, in the Central region of the state, is the one that suffers most due to being a major producer of tangerines, while the area with the lowest incidence is the Triângulo Mineiro.

Controlling the disease vector can be done by applying pesticides to orchards. The product must be indicated by an agronomist using the agronomic recipe, which must accompany the application, as required by law. 

IMA's work is to inspect properties in regions with a higher incidence of the pest to check whether the sanitary measures provided for by law are being adopted. The body also carries out phytosanitary surveys in these regions to take protective measures as soon as possible, in addition to carrying out raising awareness among producers and professional associations in the sector.

The official recommendation is that the producer inspects his orchard on a recurring basis, however the legislation requires that there be a documented inspection every three months in the municipalities where HLB occurs and in neighboring municipalities. To do this, the producer must hire an agronomist who has completed the CFO course, taught by IMA. Every six months, the producer must send a report to the agency with the information from this inspection. The report for the first semester must be sent by July 15th and the reports for the second semester must be sent by January 15th of the following year.

Impacts on the sector

The impact of the presence of HLB/greening on citrus production is great. The fruit, both for industries and for the consumer's table, has no outlet on the market. It is not possible to eliminate the disease, but it is possible, through monitoring plantations, to reduce the incidence of the pest, reducing producers' losses.

To give you an idea, according to the Brazilian Institute of Geography and Statistics (IBGE), in 2022, the Brazilian citrus sector generated more than R$14 million. In the same year, Minas Gerais was responsible for just over R$1 million, being the second largest orange producer in the country, behind only São Paulo with almost R$11 million.

According to the Citrus Defense Fund (Fundecitrus), in 2023 the citrus belt, made up of São Paulo, Triângulo Mineiro and Southwest of Minas, produced the equivalent of 314 million boxes of oranges. The forecast for 2024 is 307 million boxes of fruit, a drop of 0,7%. Also according to Fundecitrus, the incidence of greening is also one of the factors that explains the drop in this year's production estimate.

The disease

One of the great dangers of HLB/greening is that the plant can remain asymptomatic for a period of six months to two years, making detection of the disease difficult. When it manifests itself, the disease can be identified by more yellowish branches, what technicians call a mosaic, where it is possible to identify different colors of green within the same leaf, symmetrically on the right and left sides. In the fruit, there is a deformation in which one side becomes larger than the other and the seeds are aborted.

Another characteristic of the disease is the vectors' preference for younger leaves, which is why the rainy season, when there are more sprouts, is the most favorable for contamination. If the period of greatest contamination by HLB is the rainy season, the disease is most noticeable during the dry period, when the plant, in a state of stress, is able to show symptoms more easily.

The transit of vegetables is one of IMA's biggest concerns, as contaminated seedlings, when transported from one place to another, can spread the disease. The disease spreads through the so-called “ray effect”, which, from a central point, reaches the surrounding areas of plantations through natural dissemination, that is, the psyllid installed in a given location flies and looks for other areas suitable for its installation.

If HLB is suspected in areas where the pest is prevalent, the producer must contact the technical person responsible for their production, an agronomist, who will inspect the plants and, if the disease is confirmed, must proceed with eradication. In areas where there is no history of the disease, the producer must contact the IMA immediately. If the diagnosis is positive, IMA informs the entire production chain in the region so that everyone adopts the necessary health measures.

Producers who are going to bring seedlings from other states in Brazil must first contact the IMA and request authorization.