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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Efficacy of Area-Wide Inoculum Reduction and Vector Control on Temporal Progress of Huanglongbing in Young Sweet Orange Plantings

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Bassanezi, Renato B. [1] ; Montesino, Luiz H. [1] ; Gimenes-Fernandes, Nelson [1] ; Yamamoto, Pedro T. [2] ; Gottwald, Tim R. [3] ; Amorim, Lilian [4] ; Bergamin Filho, Armando [4]
Total Authors: 7
[1] Fundo Def Citricultura, Dept Cient, BR-14807040 Araraquara, SP - Brazil
[2] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz, BR-13418900 Piracicaba, SP - Brazil
[3] USDA ARS, USHRL, Ft Pierce, FL 34945 - USA
[4] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz, Dept Fitopatol & Nematol, BR-13418900 Piracicaba, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: PLANT DISEASE; v. 97, n. 6, p. 789-796, JUN 2013.
Web of Science Citations: 51

Huanglongbing (HLB), caused by `Candidatus Liberibacter' spp. and transmitted by the Asian citrus psyllid Diaphorina citri (ACP), is an important threat to citrus industries worldwide, causing significant yield loss. The current recommended strategies to manage HLB are to eliminate HLB-symptomatic trees to reduce sources of bacterial inoculum and to apply insecticides to reduce psyllid vector populations. The objective of this study was to assess the effectiveness and the importance of both strategies applied within young citrus plots (local management), in different frequencies and combinations, on HLB temporal progress. Two factorial field experiments, E1 and E2, were initiated in a new plantation of sweet orange in an HLB epidemic region of Sao Paulo, Brazil, in October 2005 and May 2006, respectively. Local inoculum reduction (tree removal) intervals for E1 were every 4, 8, and 16 weeks and, for E2, every 2, 4, 12, and 26 weeks. Local vector control strategies for E1 were no control, program A (PA), and program B (PB); and, for E2, no control and program C (PC), as follows. Psyllids were controlled with two 56-day-interval soil or drench applications of systemic insecticides concurrently with the rainy season each year and, during the rest of the year, with insecticide sprays every 28 days for PA and every 14 days for PB and PC. Regional HLB management was present for E1 and absent for E2. The beginning of the HLB epidemic was delayed for 10 months in E1 compared with appearance of the first diseased tree in E2 but wasn't affected by different local strategies in either experiment. After 60 (E1) and 53 (E2) months, the HLB incidence and progress rates were not affected by different frequencies of local inoculum reduction in either experiment, and were different only in plots with and without local vector control in E2. In E1, the disease incidence was reduced by 90% and the disease progress rate by 50% in plots both with and without vector control. These reductions were explained by smaller psyllid populations and lower frequency of bacterialiferous psyllids in E1 compared with E2. Annual productivity increased over time in E1, as expected for young plantings, but remained stable or decreased in E2. These results confirm that immigration of bacterialiferous ACP vectors plays a critical role in HLB epidemics and suggest that area-wide inoculum reduction and ACP management strongly affect HLB control. (AU)

FAPESP's process: 05/00718-2 - Studies on the bacterium Candidatus Liberibacter spp., causal agent of citrus huanglongbing (ex-greening): diagnosis, biology and management
Grantee:Marcos Antonio Machado
Support type: Research Projects - Thematic Grants
FAPESP's process: 07/55013-9 - Molecular epidemiology and integrated management of Huanglongbing (asiaticus and americanus) in the State of São Paulo
Grantee:Armando Bergamin Filho
Support type: Research Projects - Thematic Grants