Brazil’s primary citrus region recorded a significant increase in the average number of HLB-spreading psyllids captured in the first half of August compared to the previous fortnight and the same period of 2022. In the citrus belt of São Paulo and Triângulo/Sudoeste Mineiro, there was an average growth of 80.4% in the capture of psyllids in the last fortnight compared to the previous one. Compared to the same period last year, the increase is 53.2%.
Population increases of psyllids were observed in the regions of Araraquara, Casa Branca, Avaré, Santa Cruz do Rio Pardo, Bebedouro, Frutal, Itapetininga, Novo Horizonte, Franca, Limeira, São José do Rio Preto, Brotas and Jales.
FACTORS BEHIND THE INCREASE
The increase in the psyllid population classifies all regions of the citrus belt as extreme risk. In addition to the abundant vegetative flow and the favorable climate, the psyllids’ resistance to pyrethroid and neonicotinoid insecticides is a primary factor contributing to the extreme situation.
“Historically, this period of the year is one of intense capture,” said Fundecitrus researcher Marcelo Miranda. But he said psyllid resistance to the insecticides and the increase in vegetative indexes “are above those observed in the previous year in almost the entire period of 2023.”
INSECTICIDE GUIDELINES REINFORCED
Miranda said the extreme risk scenario reinforces the need for growers to put into practice guidelines by Fundecitrus. “At the time of spraying, the citrus grower needs to choose effective products, rotate the modes of action, work with adequate frequency and redouble the care in the quality of the application,” the researcher said.
Another extremely important measure is the audit of the orchards. “It is necessary to check if the applications are being carried out correctly, if the spray coverage is above 30%, mainly in the upper part of plants with heights above 5 meters,” Miranda said.
MAKE MONITORING ROUTINE
Inspection of plants for the detection of adult psyllids and nymphs should also be part of routine care, said Fundecitrus researcher Renato Bassanezi. Bassanezi explained that psyllids’ presence will indicate control failures and the need for a new application of insecticide.
Regionalized management actions involving neighboring citrus growers are also essential. They can directly impact the decline in psyllid capture when done correctly and jointly.
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