“Greening has been on the rise in the State of São Paulo, and there are no signs of a decrease or slowdown in the spread of the disease…”
Pedro Takao Yamamoto is a professor at the Luiz de Queiroz School of Agriculture (ESALQ) and holds a PhD in plant production from the São Paulo State University Júlio de Mesquita Filho.
Pedro Takao, professor at ESALQ
AgriBrasilis – What is the future of citrus farming and greening in Brazil?
Pedro Takao – Citrus farming is undergoing a geographical shift, with plantations being established in other states such as Minas Gerais, Mato Grosso do Sul, Goiás, and Bahia. This is due to the increased incidence of greening in the state of São Paulo.
This change brings challenges related to the climate in some regions and labor shortages, among others. Greening has increased in São Paulo, and there are no signs of a decrease or slowdown in the spread of the disease.
AgriBrasilis – Will São Paulo cease to be the largest producer?
Pedro Takao – It will not cease to be, but there will be a greater balance between the producing states, where planting has increased, including with the migration of farmers from São Paulo. In addition, there are also cases of local farmers who have migrated to citrus production.
AgriBrasilis – Why are cases of greening continuing to increase?
Pedro Takao – With the increase in the incidence of the disease, there is a higher rate of infectious psyllid individuals, and with that, greater transmission of the disease, causing it to snowball.
Obviously, we will have years with more transmission of the bacteria and others with less transmission, the biggest factor being the climate. Temperature greatly influences transmission.
“The most common way to overcome resistance is, first, to stop using the insecticide…”
AgriBrasilis – What are the difficulties in controlling psyllids?
Pedro Takao – We can highlight: high reproductive capacity, intense movement between fields and properties, failures in controlling plant tips due to application technology, inadequate protection of shoots, and cases of resistance.
AgriBrasilis – How can the problem of insecticide resistance be overcome?
Pedro Takao – The selection of the resistant psyllid population occurs due to the repeated and sequential application of the same insecticide.
The most common way to overcome resistance is, first, to stop using the insecticide with suspected or proven resistance, that is, not to use it for a while, because in the absence of selection pressure, the population tends to reestablish susceptibility.
Another important aspect is to rotate insecticides with different modes of action, i.e., establish an insecticide resistance management program.
AgriBrasilis – What are the challenges of adopting biological control?
Pedro Takao – Biological control faces several challenges. The first is cultural: farmers are used to killing insects, not breeding them. Despite advances in adoption, some farmers still do not believe in the effectiveness of biological control, meaning it is a problem of low credibility.
The need for skilled labor and technical knowledge to apply it and determine the exact moment of application causes farmers to give up. In addition, the lack of specialists to help guide farmers may be another factor in its low adoption rate.
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