Influence of Environment on Atmospheric Concentrations of <i>Peronospora antirrhini</i> Sporangia in Field-Grown Snapdragon

Byrne, J. M.; Hausbeck, M. K.; Sconyers, L. E.

doi:10.1094/pd-89-1060

Cited by 10 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fluctuations in hourly sporangial counts throughout the day were observed, with peak concentrations occurring in the morning and early afternoon, as shown by this study and previous studies on Pseudopenmospora cubensis (20,51) and other downy mildew pathogens (9,29). Air turbulence also peaks around mid-morning, which allows for long-distance movement of sporangia (4).…”

Section: Discussionsupporting

confidence: 82%

“…Sporangia are liberated from the underside of leaves following a reduction in relative humidity (RH) when hygro.scopic twisting movements of sporangiophores actively release sporangia into air currents (36). Hence, sporangia for most downy mildew pathogens, including P. cubetisis, are dispersed during the morning and early afternoon (9,20,26) following a decrease in RH (53). When concentrations of spores of P. cuben-.sis and other fungal pathogens were monitored in a watermelon field in a study in Florida (51 ), /Í cubensis sporangia were primarily detected in the early to mid-morning, shortly after the dew dried and surface winds increased.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Dynamics of Pseudoperonospora cubensis Sporangia in Commercial Cucurbit Fields in Michigan

Granke

Hausbeck

2011

Plant Disease

Self Cite

View full text Add to dashboard Cite

Granke, L. L.. and Hausbeck, M. K, 2011, Dynamics of Pseudoperonospora cubensis sporangia in commercial cucurbit fíelds in Michigan. Plant Dis. 95:1392-1400.Major outbreaks of cucurbit downy mildew have been observed since 200.5 in Michigan, the top state for pickling cucumber production in the United States. Airborne concentrations of Pseudoperotwspora ctibensis sporangia were monitored from 2006 to 2009 in a commercial cucurbit field in each of five Michigan counties. Temperature, relative humidity, leaf wetness, and rainfall were recorded on site in 2008 and 2(X)9. Seasonal and daily trends for sporangial concentrations were examined using loess regression to determine when sporangia were present throughout the growing season. Airborne sporangia were detected from June through September, and concentrations increased during this period. Peak airborne sporangial concentrations occurred between 8:00 and 13:00 h. Airborne sporangial concentrations were positively correlated with temperature (/• = 0,17 to 0.38, P < O.O(X)1) and negatively correlated with relative humidity (r = -0.16 to -0.45, P < 0.0046) and leaf wetness (r = -0,14 to -0,39, P < (),(X)OI) in 2008 and 2009 at all sites. In autoregressive moving average models, sporangial concentrations were negatively related to relative humidity (slope = -0.03 to -1.34, P < 0.0496) at three of five sites in 2(H)8 and four of five sites in 2009. Hence, sporangia are likely to be airborne above the crop canopy during periods with high temperatures and low relative humidity and leaf wetness.

show abstract

Section: Discussionsupporting

confidence: 82%

mentioning

confidence: 99%

Dynamics of Pseudoperonospora cubensis Sporangia in Commercial Cucurbit Fields in Michigan

Granke

Hausbeck

2011

Plant Disease

Self Cite

View full text Add to dashboard Cite

show abstract

“…Peronospora effusa detection increased exponentially over the course of growing seasons both in 2013 and 2014, consistent with other spore trapping studies (Byrne et al 2000(Byrne et al , 2005Carisse and Philion 2002;Granke and Hausbeck 2011). In the case of an obligate biotroph such as P. effusa, it is probable that the exponential increase in airborne inoculum is driven by host availability in the Salinas Valley.…”

Section: Discussionsupporting

confidence: 87%

Season-Long Dynamics of Spinach Downy Mildew Determined by Spore Trapping and Disease Incidence

Choudhury

Koike

Fox³

et al. 2016

Phytopathology®

View full text Add to dashboard Cite

Peronospora effusa is an obligate oomycete that causes downy mildew of spinach. Downy mildew threatens sustainable production of fresh market organic spinach in California, and routine fungicide sprays are often necessary for conventional production. In this study, airborne P. effusa spores were collected using rotating arm impaction spore trap samplers at four sites in the Salinas Valley between late January and early June in 2013 and 2014. Levels of P. effusa DNA were determined by a species-specific quantitative polymerase chain reaction assay. Peronospora effusa was detected prior to and during the growing season in both years. Nonlinear time series analyses on the data suggested that the within-season dynamics of P. effusa airborne inoculum are characterized by a mixture of chaotic, deterministic, and stochastic features, with successive data points somewhat predictable from the previous values in the series. Analyses of concentrations of airborne P. effusa suggest both an exponential increase in concentration over the course of the season and oscillations around the increasing average value that had season-specific periodicity around 30, 45, and 75 days, values that are close to whole multiples of the combined pathogen latent and infectious periods. Each unit increase in temperature was correlated with 1.7 to 6% increased odds of an increase in DNA copy numbers, while each unit decrease in wind speed was correlated with 4 to 12.7% increased odds of an increase in DNA copy numbers. Disease incidence was correlated with airborne P. effusa levels and weather variables, and a receiver operating characteristic curve analysis suggested that P. effusa DNA copy numbers determined from the spore traps nine days prior to disease rating could predict disease incidence.

show abstract

“…Unlike what is observed for P. infestans (2) and some downy mildew pathogens (5,18), atmospheric P. capsici sporangial con- centrations did not display a clear diurnal pattern in either field. Only rainfall was statistically associated with dispersal.…”

Section: Capsicicontrasting

confidence: 80%

Dispersal and Movement Mechanisms of Phytophthora capsici Sporangia

Granke¹,

Windstam²,

Hoch³

et al. 2009

Phytopathology®

Self Cite

View full text Add to dashboard Cite

Understanding the mechanisms of Phytophthora capsici sporangial dissemination is paramount to understanding epidemic initiation and development. Direct laboratory observations showed P. capsici sporangial dispersal occurred in water with capillary force, but did not occur in response to wind or a reduction in relative humidity. Atmospheric sporangial concentrations were monitored under field conditions using a volumetric spore sampler in a commercial cucurbit field and in an experimental setting where copious sporangia were continuously available in close proximity to the spore trap. Dispersal was infrequent (0.7% of total hours monitored) during sampling in a commercial field; 14 sporangia were detected during a 7.5-week sampling period. In the experimental field situation, dispersal occurred in 4.6% of the hours sampled and 438 sporangia were impacted onto tapes during a 7-week sampling period. Airborne sporangial concentrations were positively associated with rainfall at both sites, but not vapor pressure deficit. Furthermore, in the experimental field situation, wind speed was not significant in regression analysis. Wind speed was not measured in the commercial field. Hence, both direct laboratory observations and volumetric spore sampling indicate that dispersal of sporangia via wind currents is infrequent, and sporangia are unlikely to be naturally dispersed among fields by wind alone.

show abstract

Influence of Environment on Atmospheric Concentrations of Peronospora antirrhini Sporangia in Field-Grown Snapdragon

Cited by 10 publications

References 19 publications

Dynamics of Pseudoperonospora cubensis Sporangia in Commercial Cucurbit Fields in Michigan

Dynamics of Pseudoperonospora cubensis Sporangia in Commercial Cucurbit Fields in Michigan

Season-Long Dynamics of Spinach Downy Mildew Determined by Spore Trapping and Disease Incidence

Dispersal and Movement Mechanisms of Phytophthora capsici Sporangia

Contact Info

Product

Resources

About