Could Greening End Citrus Farming in the State of São Paulo, Brazil?

“The future of São Paulo’s citrus industry depends on the actions of each person in the sector…”

Marcelo Pedreira de Miranda is a scientific researcher and coordinator of the entomology area at Fundecitrus, professor of the MasterCitrus professional plant health M.Sc. course, member of the Protecitrus Technical Committee and of the Greening Tactical Committee.

Miranda has a degree in agricultural engineering from the Federal University of Recôncavo da Bahia, a M.Sc. and Ph.D. from Esalq/USP.

Marcelo Pedreira, coordinator of the entomology area at Fundecitrus

AgriBrasilis – Could greening end citrus farming in the State of São Paulo?

Marcelo Miranda – No. The Brazilian citrus belt that comprises the State of São Paulo and part of the State of Minas Gerais is the main orange and orange juice producing region in the world.

The State of São Paulo is the main citrus farming area in the world, with high yields. Today, more than 80% of the research work carried out by Fundecitrus is aimed at combating the spread and control of greening.

The future of São Paulo’s citrus industry depends on the actions of each person in the sector. It depends on the citrus farmer, who must strictly adopt control measures. It depends on the government, which must support the sector and monitor whether measures are being adopted. And it also depends on researchers, who need to look for more sustainable and effective control solutions.

“Containing greening in its early stages is decisive for success”

AgriBrasilis – How is the disease transmitted?

Marcelo Miranda – Generally speaking, greening is transmitted by a small insect, known as a psyllid, which feeds on the sap of all citrus varieties and of orange jasmine (Murraya paniculata). When feeding on the diseased plant, the psyllid acquires the bacteria and starts infecting other plants.

AgriBrasilis – How to control psyllids and greening?

Marcelo Miranda – To maintain a region free of the disease, or at low levels of incidence, it is very important that all states adopt in their legislation the mandatory production of citrus seedlings in protected nurseries, so that only healthy seedlings reach the orchards.

It is important to rigorously evaluate the farming microregion, eliminating or replacing citrus plants that do not receive adequate control, that is, those that can serve as a source of inoculum for the bacteria that causes the disease, where the psyllid reproduces.

If there is a low incidence, it is extremely important that diseased plants are eliminated from commercial orchards, to prevent the spread of the disease. While the incidence is low, control is easier and has less financial impact on the business. Furthermore, effective control of the psyllid is essential to keep greening at a low incidence. Fighting the spread of greening during its early stages is decisive for success. And the actions must be adopted jointly, by all citrus farmers in a given region. Hence the importance of awareness.

AgriBrasilis – What are the most efficient insecticides against this insect? What about biological control?

Marcelo Miranda – Fundecitrus coordinates the ProteCitrus list, responsible for listing products authorized for use in the farms based on the demands of consumer markets. We know that, based on research, some insecticides from the group of pyrethroids, neonicotinoids and, more recently, malathion, which belongs to the chemical group of organophosphates, are not showing adequate effectiveness in controlling the psyllid, due to the insect’s resistance to these products. The rotation of insecticides with different modes of action provides the best results in insect control.

Fundecitrus provides citrus farmers with a tool called “Avalia Psilídio” (Evaluate Psyllid) , which allows farmers to consult the results of the effectiveness of insecticides for controlling psyllids in different regions of the Brazilian citrus belt. Thus, the tool helps the citrus farmer when choosing the appropriate products to use in the orchard.

In addition to chemical insecticides, biological insecticides are being studied. Fundecitrus will soon make the results of this research available.

Repetitive use of insecticides without proper rotation of modes of action has resulted in the selection of resistant psyllids. The population growth of the psyllid in the citrus belt of the State of São Paulo is mainly related to the repetitive use and without adequate rotation of products from the chemical group of pyrethroids, neonicotinoids and, more recently, the chemical group of organophosphates.

AgriBrasilis – Are there differences in the effectiveness of products depending on the citrus growing region and the psyllid population? Why?

Marcelo Miranda – In general, it is possible to see on the “Avalia Psilídio” platform that the effectiveness of the products maintains a standard in all regions of the citrus park. However, within the same region there may be differences in the effectiveness of a given product.

In regions of expansion, such as in the States of Mato Grosso do Sul or Minas Gerais, where there is a lower density of orchards and low populations of psyllids, the behavior of insecticides can be different, as there is less probability of resistance to the aforementioned chemical groups occurring. Therefore, it is very important that an adequate rotation of insecticides is carried out in these areas so that resistance does not become a problem in the future.

AgriBrasilis – What are the results of applying neonicotinoids via “drench” to control this pest?

Marcelo Miranda – In September, Fundecitrus released preliminary results on the application of neonicotinoids via drench. At the time, tests carried out on a property in Casa Branca, State of São Paulo, showed that the efficiency of the molecules for this type of application was low (mortality of adult psyllids was less than 40%).

The research advanced and new evaluations were carried out. As the results represent the reality only in the places where the research was carried out, this efficiency cannot be generalized to the entire region. Maintaining or restoring the high efficiency of neonicotinoids will depend on correct rotation within the property and on neighboring properties.

AgriBrasilis – What is the “Avalia Psilídeo” tool and what are its benefits for citrus farmers? What other Fundecitrus projects are underway?

Marcelo Miranda – Launched in January of 2024, the “Avalia Psilídeo” tool is the result of joint work that involved the citrus farmers and several sectors of Fundecitrus, including the Technology Transfer teams, which collect the insect, the R&D team, responsible for experiments with psyllids, etc.

Knowing which products are better and in which region is important and will contribute to greening management. Fundecitrus’ mission has always been to guide and inform citrus farmers on issues involving good phytosanitary practices.

With the advancement of greening in orchards, Fundecitrus redoubled its actions in the farms, with communication actions, training, lectures, meetings with farmers, external actions and research. Our researchers and our team of agronomists are constantly talking to farmers and warning them about prevention measures. Avalia Psilídio is another way for us to work to raise awareness and disseminate information.



Citrus Canker Threat in the State of Minas Gerais, Brazil