Researchers Discuss Rising HLB Incidence in Brazil

Daniel CooperBrazil, HLB Management

Presentations at Expocitrus in Brazil addressed HLB management.
Photo courtesy of Fundecitrus

The incidence of citrus greening disease (HLB) in Brazil’s Citrus Belt of São Paulo and Triângulo/Southwest Mineiro rose from 24.42% in 2022 to 38.06% in 2023, according to Fundecitrus. The association’s annual survey indicates the disease increasingly demands more effective and collaborative measures.

At a session of Brazil’s Expocitrus in June, Fundecitrus researcher Marcelo Miranda discussed the development of greening management measures recommended for the disease’s insect vector.

“Knowing all the characteristics of the insect and measures that can control it is very important given the complexity of the disease,” Miranda said.

Also at Expocitrus, Fernando Semmelroth de Assunção e Amaral, post-doctoral fellow from the University of São Paulo at Fundecitrus, discussed psyllid resistance to insecticides in Brazil. Since last year, citrus growers have been facing cases of psyllid resistance to certain chemical groups of insecticides, such as pyrethroids, neonicotinoids and organophosphates.

“Based on work with populations resistant to these three chemical groups, it is possible to study and better understand how to manage these resistant insects in the field,” Amaral said. “Some experiments have shown the presence or absence of cross-resistance with other insecticides that are also being used in management. This helps to strengthen the most important strategy for managing resistance, which is the rotation of insecticides with different modes of action.”

Another Fundecitrus researcher, Franklin Behlau, presented a lecture at Expocitrus about plant growth regulators for reducing premature fruit drop in orange trees affected by HLB.

“These regulators have been used intensively in sick orchards in the United States and, in some cases, there are interesting results,” Behlau said. “The advances in these studies for the development of techniques to reduce the impacts of greening are of great interest to our citrus industry.”

Behlau said measures that prevent the occurrence of HLB are still necessary. Those measures include controlling the psyllid that spreads the disease, quality of application, rotation of modes of action, inspection of orchards and elimination of diseased plants.

Source: Fundecitrus

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