Discharge of<i>Venturia inaequalis</i>ascospores during daytime and nighttime wetting periods in Ontario and Nova Scotia

Warner, John T.; Braun, Peter

doi:10.1080/07060669209500870

Cited by 11 publications

(4 citation statements)

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“…For a number of species, few spores are found in the air at night, with a sharp increase in spore release in the early morning after a moist night during which spores are produced (Langenberg et al 1977, Couture & Sutton 1978). Other plant pathogenic fungal species release most spores later in the day (Leach et al 1977, Raynal 1990, Carisse & Philion 2002), in the late afternoon (Hock et al 1995), or at night (Warner & Braun 1992, Stensvand et al 1998, Fernando et al 2000). In studies over sugar cane fields, Bhagawan and Pande (1988) found that fungal species differed in whether they produced spores primarily at night or in the early morning.…”

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confidence: 99%

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest¹

Gilbert

Reynolds

2005

Biotropica

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Pathogens and other symbiotic fungi that infect above-ground plant parts commonly disperse as airborne spores. Here we present diel patterns of the density of airborne fungal spores in the canopy and understory of a tropical rain forest. Spores were 52-fold more abundant in the understory than in the canopy. Additionally, spores were 5-to 35-fold more abundant at night than during the day, associated with environmental conditions conducive to germination and plant infection. RESUMENLos hongos patógenos y otros hongos simbióticos que colonizan las hojas y tallos de plantas se dispersan comunmente como esporas en el aire. Aquí presentamos patrones diarios de la densidad de esporas de hongos en el aire en el dosel y en el sotobosque de un bosque tropical lluvioso. Las esporas son 52 veces más abundantes en el sotobosque que en el dosel. Ademas, las esporas fueron 5-a 35-veces más abundantes en la noche que durante el día, con la mayor abundancia de esporas asociada con las condiciones ambientales adecuadas para la germinación e infección de plantas. TROPICAL ECOLOGISTS ARE ACCUSTOMED TO ORGANISMS ACTIVE during different times of the day-the raucous chatter of birds in the early morning, frog choruses in the evening, diurnal CO 2 acquisition for C 3 plants, and nocturnal acquisition for those with CAM photosynthesis, crepuscular mosquitoes, and prowling nocturnal predators. Like big cats, tropical fungi may lead a largely nocturnal life. Here we present quantitative diel patterns for airborne fungal spores in the canopy and understory of a lowland tropical rain forest.We measured the concentration of airborne fungal spores during the early rainy season in the canopy (24 m above ground near the top of an Acmena graveolens (Myrtaceae) tree) and below it in the understory (1.5 m) of the tropical rain forest at the Australian Canopy Crane Research Facility, Cape Tribulation, Queensland, Australia (16• 06 S, 145• 27 E; alt. 31-55 m). The site is in the Wet Tropics World Heritage Area, and includes complex mesophyll vine forest with an irregular canopy from 15 to 33 m tall. The site averages 3600 mm rain annually, with 70 percent usually falling between December and April. See Stork and Cermak (2003) for a detailed description of the site and facilities.We captured airborne fungal spores onto petroleum jellycoated microscope slides using two Alergenco MK-3 volumetric air samplers (Alergenco, San Antonio, TX). The samplers automat- ically captured spores for 10-min periods at either half-hour or hour intervals. The captured spores were quantified by staining slides with augmented Calberla's solution, then counting all fungal spores in four fields of view at 400 or 1000× (Olympus CH-2 microscope, Olympus Inc., Melville, NY), depending on spore density. Fields of view were chosen haphazardly within a spore trace by selecting the spot to sample while looking directly at the slide on the microscope stage, rather than through the lenses. Each field of view at 400× covered 0.1616 mm 2 , and 0.0259 mm 2 at 1000×. The spor...

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confidence: 99%

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest¹

Gilbert

Reynolds

2005

Biotropica

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“…releases its first spores with a 1-7-h delay for the onset of rain, and the maximum number of spores is obtained when rain has remarkably weakened or ended (AYLOR and SuTTON 1992). Dew is also often mentioned as an initiating factor for spore release, especially with plant pathogens sporulating in summer (AYLOR and SuTTON 1992;WARNER and BRAUN 1992;SPOTTS and CERVANTES 1994). Although dew is most abundant in September in Finland (HuoviLA 1968), it was seldom the only wetting factor in the initiation of spore release.…”

Section: Discussionmentioning

confidence: 99%

Short‐term variation in ascospore release by Phacidium infestans on the needles of Pinus sylvestris

Kurkela

1995

European Journal of Forest Pathology

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Aseospore release hy Pbaeidium infestans was monitored with volumetric-recording spore traps in Finland. Detached branches of Scots pine infeeted naturally during the previous winter were used as a spore source. Spores were trapped during two autumns with simultaneous recording of weather factors. Free water from rain or thawing of rime or snow on the needles was required to initiate the spore release. After the onset of rain, the number of spores reaehed its maximum in 4-6 h, while heavy rain decreased the liberation of spores into the air. The number of spores had a higher correlation both with relative humidity and with preeipitation delayed 3-7 li than with current precipitation. Temperature did not directly affect the aseospore release. Only a few spores were trapped at temperatures below 0°C. The effect of wind on the release of spores was mainly negative, and lndireet through decreasing humidity. No diurnal periodicity was detected in the spore release.

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“…The vacuum method has the advantage of collecting spores continuously through a rotating disc or on a roll of tape, therefore allowing the user to compare spores collected with weather data of the same time period (Rossi et al 2001). Previously it has been shown that ascospores were mainly discharged during daytime hours in rain events at a rate of up to 4250 spores h −1 per cubic metre air (MacHardy 1994;Warner and Braun 1992;reviewed in MacHardy 1996). The Rotorod-type spore trap and the VST have been used in combination with quantitative PCR (qPCR) for detection of inoculum from other air-borne plant pathogen inoculum; e.g.…”

Section: Introductionmentioning

confidence: 98%

“…These harbour asci with ascospores, which are discharged once they are mature in spring and peak 5-9 weeks after bud break between the phenological stages of pink tip and full apple bloom, depending on humidity and temperature (MacHardy, 1996). To predict timing and risk of scab infection, weather data based models were developed, which determine fungicide application schedules (Mills and Laplante 1951;Gadoury and MacHardy 1986;Warner and Braun 1992;Gadoury et al 1998;Stensvand et al 2005;Rossi et al 2007). Ideally weather models should be combined with an assessment of ascospore maturity and quantification of potential inoculum dose (Gadoury and MacHardy 1986;MacHardy et al 1993).…”

Section: Introductionmentioning

confidence: 99%

A method to monitor airborne Venturia inaequalis ascospores using volumetric spore traps and quantitative PCR

et al. 2014

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Apple scab caused by the fungus Venturia inaequalis can result in significant crop losses if not managed effectively. Sanitation as part of an integrated management strategy aims to significantly reduce primary inoculum to lower the disease pressure. This study evaluates the possibility of molecular detection and quantification of ascospore discharge and the use of this method to test for efficacy of orchard sanitation treatments. A method to detect and quantify airborne ascospores was developed using volumetric spore traps (VSTs). V. inaequalis specific primers were tested on daily VST samples from two orchard sections (leaf litter removed compared to leaf litter left) during spring. A molecular method to detect and quantify ascospores was tested by amplifying genomic regions of the mitochondrial CYP51A1 gene, and the ITS region using SYBR® green. Timing of ascospore discharge was compared to predicted infection risk and a degree day model using weather data. The average spore detection limit was estimated to be at levels of 1 pg μl −1 DNA (approximately 37 ascospores) per daily spore trap reading using CYP51A1 primers. Using the CYP51A1 primer pair, primary inoculum was estimated to be 51 % lower in the orchard sections where leaves had been removed, indicating that this method could be used to evaluate the efficacy of alternative control strategies such as leaf removal to reduce potential ascospore dose. This is the first report of combining VSTs and quantitative PCR to monitor airborne V. inaequalis ascospores.

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Discharge ofVenturia inaequalisascospores during daytime and nighttime wetting periods in Ontario and Nova Scotia

Cited by 11 publications

References 6 publications

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest¹

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest¹

Short‐term variation in ascospore release by Phacidium infestans on the needles of Pinus sylvestris

A method to monitor airborne Venturia inaequalis ascospores using volumetric spore traps and quantitative PCR

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Discharge ofVenturia inaequalisascospores during daytime and nighttime wetting periods in Ontario and Nova Scotia

Cited by 11 publications

References 6 publications

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest1

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest1

Short‐term variation in ascospore release by Phacidium infestans on the needles of Pinus sylvestris

A method to monitor airborne Venturia inaequalis ascospores using volumetric spore traps and quantitative PCR

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Product

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About

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest¹

Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest¹