O modelo autologístico espaço-temporal para dados de doenças em plantas.

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Progresso espaço-temporal da leprose dos citros.

A leprose dos citros tem sido considerada uma das mais importantes doenças da citricultura brasileira, pois reduz a produção e o período de vida das plantas afetadas (Rodrigues et aI., 2003), ocorre em quase todos os estados do País que produzem citros e é considerada endêmica no Estado de São Paulo. Esta doença é causada pelo Citrus feprosis vírus (CiLV) transmitido exclusivamente, nas condições de campo, pelo ácaro Brevipalpus phoenícis Geijskes (Acari: Tenuipalpidae), conhecido vulgarmente como ácaro plano ou ácaro da leprose

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

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 miteinfested 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. Keywords: Brevipalpus yothersi, Citrus leprosis virus, Citrus sinensis, epidemiology, flat mite, spatial analysisPublicação impressa em: Plant Pathology, v. 68, p. 85-93, 2019