Fabrício Eustáquio Lanza, research coordinator at Brazil’s Cambuhy Agricola, recently told how his company has kept HLB at low and economically acceptable incidence levels. His presentation at the recent International Research Conference on HLB was based on a report he co-authored with Alexandre Tachibana, Ivan Brandimarte, Antonio Juliano Ayres and Renato Beozzo Bassanezi. The report follows:
MANAGEMENT MEASURES
Huanglongbing (HLB), transmitted by Diaphorina citri (Asian citrus psyllid), was identified in the central region of São Paulo State (SPS), Brazil, where the Cambuhy Agricola farm is located, in March 2004. Since its identification, the HLB management measures recommended by Fundecitrus — such as planting of healthy nursery trees, elimination of diseased trees, and vector control — were applied and strictly followed.
During the 2009–10 season, a quick increase in the disease incidence (294% compared to the previous season) was detected in the farm, which caused the removal of 3.9% of HLB-affected trees.
From there, supported by both research data and citrus grower experiences, the HLB control has been constantly improved. Measures include regional disease management, higher frequency of insecticide spray on border blocks compared to inner blocks, row orientation, and variety and rootstock selection. Today, the main measures established are:
- Inoculum reduction by frequent removal (four times per season) of symptomatic trees
- Insect population monitoring by yellow traps
- Targeted control of psyllid population by insecticide treatment
- Use of healthy trees for resets
Moreover, external management in a 5-kilometer radius was implemented by removal of citrus seedlings in permanent preservation areas, control of the psyllid vector in backyard orchards by insecticide treatment or removal of symptomatic trees, and control of the psyllid population in the commercial orchards by insecticide treatment.
HLB INCIDENCE
According to a survey published by Fundecitrus in 2019, the HLB incidence in the central region of SPS (municipality of Matão) was 17.2% while Cambuhy farm showed 1.2% of incidence. In the 2020, 2021 and 2022 surveys, the regional incidences were 14.4%, 9.7% and 8.9%, while the Cambuhy farm detections were 0.7%, 1% and 2.2%, respectively.
In the last season, all above-mentioned measures represented 19.8% of the production costs, which is more profitable compared to having a 100% diseased orchard. Therefore, to control the disease and obtain financial return, Cambuhy Agricola performs all HLB management measures, including internal and external management.
SUMMARY
The adoption of continuous and rigorous control of Asian citrus psyllids and removal of all HLB-symptomatic trees since the beginning of the HLB epidemic, both inside the citrus farm and in a 5-kilometer radius in neighboring commercial and non-commercial citrus areas, has kept HLB at low and economically acceptable incidence even in a region where the disease is endemic in the center of São Paulo’s Citrus Belt. This can be considered a case of success in HLB control and proves that area-wide psyllid and inoculum control are effective to manage disease.
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