Analysis of the temporal and spatial disease progress of Bemisia tabaci‐transmitted Cucurbit yellow stunting disorder virus and Cucumber vein yellowing virus in cucumber

Abstract

Cucurbit yellow stunting disorder virus (CYSDV) has been present in greenhouse-grown cucumber in Spain since 1992. However, in the autumn of 2000 Cucumber vein yellowing virus (CVYV) was introduced, leading to mixed infections of both Bemisia tabaci -transmitted viruses. The temporal and spatial spread of disease symptoms were monitored in experimental plastic-covered greenhouses during six consecutive cucumber plantings from 2000 to 2002. Using linear regression analysis of 46 disease-progress curves, the Gompertz model best described the CYSDV epidemics in 2000, whereas the logistic model best described the development of CYSDV and CVYV epidemics in 2001 and 2002. The fitted models were used to calculate the amount of degree Celsius-days at half-maximum infection in the greenhouses ( ° D 0·5 ). After multiple regression analysis, 56% of the variation in ° D 0·5 of CYSDV was related to the numbers of whiteflies infesting the cucumber crops, and was independent of the mean temperatures in the greenhouses. In contrast, 76% of the variation in ° D 0·5 of CVYV was related to both the numbers of vectors present and maximum temperature. Symptom expression in cucumbers mechanically inoculated with CVYV was most prevalent when plants were grown at regimes of at least 28 ° C day temperature. According to analysis of spread using Taylor's power law, beta-binomial distribution fitting, and the ordinary runs test, the prevalence of CVYV showed significant overdispersion, whereas that of CYSDV did not. The χ 2 test of independence and Spearman's rank correlation coefficient were used to measure co-occurrence and covariation, respectively, during the first half of the cultivation period. These results showed that the two diseases were not associated.

Temporal and spatial progress of the diseases caused by the crinivirus tomato chlorosis virus and the begomovirus tomato severe rugose virus in tomatoes in Brazil

“…(). Other spatial studies of diseases caused by begomoviruses in tomatoes (Polston et al ., ; Barbosa et al ., ) and by crinivirus in watermelons (Turechek et al ., ) and cucumbers (Ruiz et al ., ) reported similar findings, strongly suggesting that the infected plants in those fields were randomly distributed.…”

“…The association of golden mosaic disease and yellowing disease was low, except in four (Taquara) of the 16 analysed plots, as assessed by the Jaccard index. Similar low associations between viruses transmitted by the same whitefly vector were observed in a cucumber crop between Cucumber vein yellowing virus , an ipomovirus species, and Cucumber yellow stunting disorder virus , a crinivirus species (Ruiz et al ., ), as well as in a watermelon crop between a begomovirus ( Cucurbit leaf crumple virus ) and another ipomovirus ( Squash vein yellowing virus ) (Turechek et al ., ). In the present study, golden mosaic and yellowing diseases were highly associated only in the plots in Taquara, which again supports the premise that the tomato crop in the final stage of production, which was near the experimental plots, was the main source of the viral inocula.…”

Comparative Epidemiology of Three Virus Diseases on Zucchini Squash

“…This non‐association between viral diseases in simultaneous occurrence was also reported by Ruiz et al. () studying temporal and spatial progress of Cucurbit yellow stunting disorder virus (CYSDV) and Cucumber vein yellowing virus (CVYV). Although both viruses are transmitted by the same vector ( Bemisia tabaci ), the authors concluded that the diseases are not associated.…”

Biological characterization of Tomato leaf curl New Delhi virus from Spain

“…In spring of 2014, B. tabaci whiteflies carrying ToLCNDV were collected from zucchini squash plants that expressed symptoms of ToLCNDV. The plants and whiteflies were analysed by PCR to ensure the presence of ToLCNDV (primers and protocols are described below), and the absence of cucurbit viruses transmitted by B. tabaci in Spain, Cucurbit yellow stunting disorder virus and Cucumber vein yellowing virus (Ruiz et al, 2006), was confirmed by RT-PCR. A virus-free population of B. tabaci was collected from a commercial eggplant crop (Solanum melongena) in spring of 2012 and reared on eggplant (cv.…”