Temporal and spatial dynamics of Tomato spotted wilt virus and its vector in a potato crop in Argentina

Abstract

The nature of spatial and temporal dynamics of Tomato spotted wilt virus (TSWV) and its vector in a potato crop cv. Innovator without insecticide application is analysed. Seed tuber was analysed for the presence of TSWV as a source of initial inoculum. The presence of plants with symptoms of TSWV was evaluated by visual observation and DAS-ELISA analysis to confirm the virus infection. Thrips species were collected from leaves and inflorescences and identified under stereomicroscope. The distribution of symptomatic plants and thrips species was recorded five times at 14 days intervals. The initial seed tuber infection was of 1.1%. Disease incidence was 0% at 29 days after planting (DAP), 0.2% at 43 DAP, 2.2% at 56 DAP, 11.6% at 70 DAP and 14.6% at 84 DAP. The progress of the disease was adequately described by a Logistic model [y = 0.15/(1 + 1205372.93 × exp (−0.22 × DAP))]. Thrips vector species identified as resident in the crop during the whole cycle were Thrips tabaci (n = 423), Frankliniella occidentalis (n = 141) and as occasional species, F. schultzei (n = 34) and F. gemina (n = 5) were found. At 43 and 56 DAP a random distribution pattern was observed and the thrips species found were T. tabaci (n = 188) and F. occidentalis (n = 105). An aggregated pattern was determined at 70 and 84 DAP. Spatial patterns of the disease spread suggest a polycyclic epidemic with TSWV secondary spread in the potato crop. Multiple control measures were deduced from these epidemiological results like virus testing in tubers, removal of external virus infection sources and thrips control.

Viral Diseases in Potato

“…The more common species are Tomato spotted wilt virus (TSWV), Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus (TCSV) (Lima and Michereff 2016). Similar outbreaks have been described elsewhere, such as in Argentina (Salvalaggio et al 2017) and United States of America (Abad et al 2005).…”

“…In other countries, there has been evidences of tospovirus species perpetuating via tubers produced by infected plants. These observations cause concern for seed-potato production (Abad et al 2005;Salvalaggio et al 2017). Therefore, a close monitoring of the incidence of tospoviruses in Brazilian potato fields is recommended in order to control not only its dissemination in the current season but also its perpetuation by tuber seed transmission.…”

Efficiency and Persistence of Movento® Treatment against Myzus persicae and the Transmission of Aphid-Borne Viruses

“…The 10% decrease in infected plants may contribute to the improvement of the sanitary quality of the protected areas by reducing the number of virus introductions in the field. In studies carried out on other annual plant species (e.g., cereals, potato), it was shown that the overall incidence of insect-transmitted viruses relies mainly on the efficiency of secondary infections initiated from the primary infected plants [35,36]. Thus, by preventing aphids from settling on treated plants and producing their offspring, and by lowering the success of primary inoculations, Movento ® may negatively impact important steps of viral disease spread at the field level.…”

Can Winged Aphid Abundance Be a Predictor of Cucurbit Aphid-Borne Yellows Virus Epidemics in Melon Crop?

“…In the present study, CABYV progress over time (expressed as days after planting or fleece removal) was successfully described by the logistic model. This model commonly used to describe the temporal dynamics of plant viruses [16][17][18][19] has three parameters (µ, γ, α) with a biological sense (epidemic precocity, carrying capacity, epidemic speed) that were considered as dependent variables in statistical analyses and data mining. Parameters were uncorrelated.…”