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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.)

Spatial patterns of the Citrus leprosis virus and its associated mite vector in systems without intervention

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Author(s):
Bassanezi, R. B. [1] ; Czermainski, A. B. C. [2] ; Laranjeira, F. F. [3] ; Moreira, A. S. [3] ; Ribeiro Junior, P. J. [4] ; Krainski, E. T. [4] ; Amorim, L. [5]
Total Authors: 7
Affiliation:
[1] Fundecitrus, Res & Dev Dept, CP 391, BR-14801970 Araraquara, SP - Brazil
[2] Embrapa Grape & Wine, CP 130, BR-95700000 Bento Goncalves, RS - Brazil
[3] Embrapa Cassava & Fruits, BR-44380000 Cruz Das Almas, BA - Brazil
[4] Univ Fed Parana, Dept Stat, CP 19081, BR-81531990 Curitiba, Parana - Brazil
[5] Univ Sao Paulo, Plant Pathol & Nematol Dept, CP 9, BR-13418900 Piracicaba, SP - Brazil
Total Affiliations: 5
Document type: Journal article
Source: PLANT PATHOLOGY; v. 68, n. 1, p. 85-93, JAN 2019.
Web of Science Citations: 1
Abstract

Leprosis is caused by the Citrus leprosis virus cytoplasmic type and is vectored by the mite Brevipalpus yothersi. Miticide applications, which cost \$54 million annually, are based on inspection for the presence of mites. The aim of the present study was to characterize the spatial patterns of B. yothersi-infested trees and trees with leprosis symptoms for further improvement in sampling and disease control. The presence of mites and the occurrence of leprosis were assessed over two years in 1160 Valencia trees and 720 Natal trees in a commercial sweet orange grove in Sao Paulo State, Brazil. To assess the natural growth and dispersal of mites and leprosis, mite populations were not controlled during the experimental period. Maps of mite-infested trees and trees with leprosis symptoms were analysed at three different levels of spatial hierarchy using complementary methods, i.e. among adjacent trees within and across rows, within quadrats, and the strength and orientation of aggregation among quadrats. The study showed that the spatial patterns of virus-infected and mite-infested trees were different, with a strong aggregation pattern of trees with leprosis symptoms that increased over time. Conversely, the spatial pattern of B. yothersi showed randomness or weak aggregation at all three spatial hierarchical levels. Disease incidence increased steadily in plots of both cultivars, unlike in mite-infested trees where incidence fluctuated over time. These results have important implications for the development of better management strategies for leprosis. Sampling methods and action thresholds for mite control should consider primary disease inoculum in addition to the incidence of mites. (AU)