Etiology, occurrence and epidemiology of a begomovirus disease in passionflower in the southwest of Bahia

Gisele Brito Rodrigues,Lilian Amorim,Quelmo Silva De Novaes,Armando Bergamin Filho,Tatiana Mituti,Geraldo Gomes Rocha Sobrinho,Jorge Alberto Marques Rezende

doi:10.1590/1678-992x-2017-0272

Gisele Brito Rodrigues, Lilian Amorim + Show 5 more

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https://doi.org/10.1590/1678-992x-2017-0272

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Abstract

Severe mosaic symptoms, accompanied by yellow spots, abnormally small leaves, fruit malformation and cracking, reduced plant growth, and high levels of whitefly (Bemisia tabaci MEAM1) infestation were observed in passionflower (Passiflora edulis) orchards in southwestern Bahia, Brazil. The aim of this work was to identify the species of begomovirus infecting the passionflowers, its prevalence in southwestern Bahia, and the spatial and temporal dynamics of the disease. Leaf samples from symptomatic plants collected at 57 orchards located in ten counties were evaluated by PCR for begomovirus infection. Complete nucleotide sequences of DNA-A for two isolates revealed 97 % identity with Passionfruit severe leaf distortion virus (PSLDV). The occurrence of PSLDV in 57 orchards was evaluated based on the presence of characteristic disease symptoms. Approximately 235,000 visually assessed plants exhibited symptoms characteristic of begomovirus infection. Epidemiological studies, conducted in two orchards in Dom Basílio County, showed that disease progress was relatively slow until 121 days after transplanting (DAT), but more rapid in the following 35 days, reaching 100 % infected plants by 156 DAT. The exponential model was fitted to the temporal dynamic of the disease for both areas. An aggregated pattern of diseased plants was predominant for almost all evaluations. It is possible that the primary and secondary spread of the pathogen occurred concurrently during the epidemic progression in both areas, especially late in the season. Containment measures to prevent the virus and the vector from spreading to other passionfruit producing areas in Brazil should be implemented.

Highlights

IntroductionBrazil is the world’s largest producer of passionfruit, with ca
Severe mosaic symptoms, accompanied by yellow spots, abnormally small leaves, fruit malformation and cracking, reduced plant growth, and high levels of whitefly (Bemisia tabaci MEAM1) infestation were observed in passionflower (Passiflora edulis) orchards in southwestern Bahia, Brazil
Leaf samples from symptomatic plants collected at 57 orchards located in ten counties were evaluated by polymerase chain reaction (PCR) for begomovirus infection

Summary

Introduction

Brazil is the world’s largest producer of passionfruit, with ca. 825,000 tons annually, of which 46 % is produced in the state of Bahia (IBGE, 2014). During 2012-2014, passionfruit growers in southwestern Bahia faced an outbreak of disease with symptoms similar to those caused by a previously described begomovirus (Novaes et al, 2003), including mosaic accompanied by intense yellow spots on leaves, severe leaf distortion, fruit malformation and cracking (Figure 1AC), as well as reduced plant growth. The disease was accompanied by heavy whitefly infestation (Figure 1D-E), which is uncommon as passionflower is not preferred by whiteflies (Nunes et al, 2008). A similar outbreak, in the state of Bahia, was first reported by Novaes et al (2003).

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