Effect of weather factors on the release of ascospores of <i>Uncinula necator</i>, the cause of grape powdery mildew, in the Bordeaux region

Jailloux, F.; Willocquet, Laetitia; Chapuis, L.; Froidefond, Georges

doi:10.1139/b99-118

Cited by 24 publications

(29 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Late summer and autumn rains wash them onto the bark of the grapevine where they overwinter (Cortesi et al 1995(Cortesi et al , 1997. Insuffi cient autumn rains may aff ect the transfer of chasmothecia from the leaves to the bark, resulting in a residue of viable chasmothecia that survive on fallen leaves (Cortesi et al1997;Jailloux et al 1999). So, the absence of chasmothecia on grapevine bark may be explained by the lack of rain in southern Syria, especially during recent years, in autumn before the leaves fall.…”

Section: Chasmothecia Formationmentioning

confidence: 99%

Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

Alimad¹,

Naffaa²,

Azmeh³

2017

Journal of Plant Protection Research

View full text Add to dashboard Cite

Th e main aims of this study were to determine the overwintering form and the primary inoculum of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria. Eleven vineyards located at fi ve diff erent geographical sites were visited every week from March to November in 2014 and 2015. Th e results of fi eld and histopathological studies showed that E. necator survived as mycelium in dormant grapevine buds during the winter season. Th e fi rst fl ag shoots were observed shortly aft er bud break in spring. Th e number of fl ag shoots varied greatly according to vineyards, cultivars and years, being present on 27.4 to 61.9% of the grapevines in 2014, and on 5.2 to 40% of the grapevines in 2015. Th e percentage of fl ag shoots on the same grapevine also varied according to the year, cultivar and location. It was between 4.3 to 9.4% in 2014, and 2.1 to 3.6% in 2015. Th e disease was observed only on Balady and Black cultivars. Conidia were released from the second week of May to early September. Th e fi rst conidia were trapped around mid-May, and the fi rst secondary symptoms were observed on leaves from mid-May to early June according to the site. Chasmothecia were observed on leaves in 45.5% of the studied vineyards. Th e fi rst observation of chasmothecia on leaves was in July, and their numbers varied greatly between vineyards and years. Chasmothecia were not detected on bark, nor were ascospores trapped at the beginning of the season. Th ese results confi rmed that the ascospores did not have any role in the initiation of spring infection. To the best of our knowledge, this is the fi rst report of the overwintering form of E. necator in Syria.

show abstract

Section: Chasmothecia Formationmentioning

confidence: 99%

Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

Alimad¹,

Naffaa²,

Azmeh³

2017

Journal of Plant Protection Research

View full text Add to dashboard Cite

show abstract

“…Perhaps the patchiness serves to provide a steady stream of ascospores for capture of newly available substrate (newly dead leaf blades). Or perhaps we did not satisfactorily standardize our collected leaf samples; i.e., perhaps our blades were unexpectedly variable in state of decay and/ or in impact of environmental variables influencing asco-spore maturation and release such as rain, dew, tides, solar irradiation, invertebrate mycophagy (see Arseniuk et al, 1998;Graca et al, 2000;Ingold, 1971;Jailloux et al, 1999;Kurkela, 1997;Newell and Porter, 2000;Paulitz, 1996).…”

Section: Discussionmentioning

confidence: 99%

“…18 x 7 ~m) hyaline ascospores were often difficult to resolve in bright field, which was used for the other two (brownspored) species. We tested cotton-blue staining of Mycosphaerella spores (Jailloux et al, 1999); the ascospores were too lightly stained to provide improved detectability. Identities of all types of ascospores were confirmed for each coverslip by examination at x 400 (Zeiss interference contrast).…”

Section: Ascospore Expulsionmentioning

confidence: 99%

Measuring summer patterns of ascospore release by saltmarsh fungi

Newell

Zakel

2000

Mycoscience

View full text Add to dashboard Cite

One potentially important type of flux from standing-decaying marshgrass is the production and release of ascospores. The most extensive measurements of ascospore release from the principal marshgrass (Spartina alterniflora, smooth cordgrass) of saltmarshes of the eastern coastal United States involved an arbitrary, weeklong period of wet incubation of leaf-blade samples. We examined the possibility that shorter incubations would yield higher estimates of hourly rates of ascospore release, testing wet incubations of 3 to 71 h, using standing-decaying leaf blades of smooth cordgrass from low on living shoots and high on dead shoots, incubations of 31 h appeared to be optimal. Species compositions of ascospores expelled from the two leaf types were distinctly different: high leaves yielded primarily a Mycosphaerella species or Phaeosphaeria halima; low leaves yielded primarily Phaeosphaeria spartinicola or the Mycosphaerella species. All of these species consistently exhibited high coefficients of variation (>100%) for their mean rates of release of ascospores. Only the Mycosphaerella species on high leaves gave evidence of a delayed onset of ascospore expulsion during incubation, and this evidence was equivocal. Grand mean rates of ascospore release for P. spartinicola and the Mycosphaerella species were, respectively, 106 and 238 spores cm -2 abaxial leaf area h-1.Key Words ascomycetes; ascospore-expulsion rate; marshgrass; Mycosphaerella; Phaeosphaeria.Flow to secondary production by ascomycetous fungi is the primary destiny of dead shoots of smooth cordgrass (Spartina alterniflora Loisel), the highly photosynthetically productive grass of eastern USA saltmarshes (Newell, 1996;Newell and Porter, 2000), prior to movement into the marsh's trophic relay (Kneib, 1997). Newell and Wasowski (1995) attempted to measure one form of ascomycetous production from smooth cordgrass, as rate of output of meiospores (ascospores). They recorded the rate of deposition of ascospores onto target coverslips for wetted, naturally-decaying leaf blades. They used one arbitrarily chosen standard incubation period (168 h) for the ascospore-releasing blades. Newell and Wasowski (1995) counted ascospores only for the two species of ascomycetes (Phaeosphaeria spartinicola Leuchtmann and Buergenerula spartinae Kohlm. & Gessner) that they detected by direct-microscopic enumeration as the major producers of mature ascomata in naturally decaying blades low on partially living shoots. It was subsequently discovered that a prominent ascospore-producing species in standing-decaying smoothcordgrass blades is Mycosphaerella sp. 2 (of Kohlmeyer and Kohlmeyer, 1979), which has smaller, more cryptic ascomata than the ascomata of P, spartinicola with which they are often mixed (Newell and Porter, 2000). We report here our attempt to improve interpretability of the ascospore-capture technique as used with saltmarsh grasses; the resultant data add to the currently meager Corresponding author. E-mail, newell(~uga.edu definition of the spatiotemporal patte...

show abstract

“…Temperature has been well documented in terms of its influence on the grapevine host (Bogoni et al 1993;Buttrose and Hale 1973;Ferrini et al 1995;Flexas et al 1999;Greer and Weedon 2013;Hendrickson et al 2004;Keller and Tarara 2010;Parker et al 2011) and powdery mildew pathogen (Austin and Wilcox 2011;Chellemi and Marois 1991c;Choudhury et al 2014;Delp 1954;Diehl and Heintz 1987;Gadoury and Pearson 1990;Hall and Mahaffee 2001;Jailloux et al 1999;Moyer et al 2010;Peduto et al 2013;Rumbolz et al 2000). The effect of temperature on the host and pathogen is key to many forecast and disease epidemic simulation models (Bendek et al 2007;Caffi et al 2011;Calonnec et al 2008;Chellemi and Marois 1991a;Kast and Bleyer 2010;Legler et al 2012a;Moyer et al 2014;Peduto et al 2013;Sall 1980).…”

Section: Introductionmentioning

confidence: 99%

Cold Stress-Induced Disease Resistance (SIDR): indirect effects of low temperatures on host-pathogen interactions and disease progress in the grapevine powdery mildew pathosystem

et al. 2015

View full text Add to dashboard Cite

Erysiphe necator is an obligate biotroph capable of infecting three genera within the Vitaceae (Vitis, Parthenocissus, and Ampelopsis). The pathogen inhabits a niche unique to most powdery mildews, i.e., wholly external mycelial growth supported by haustoria within the subtending host epidermal cells. This growth habit coupled with its biotrophic reliance on the host makes E. necator sensitive to both direct effects of abiotic stresses on the pathogen and indirect abiotic effects via the host responses. Development of the pathogen during acute cold events (e.g., 1 h at 4°C) results in death of hyphal segments and a prolonged latency, an effect further increased by the development of ontogenic resistance as epidermal tissues of leaves and berries age. Acute cold events can also stress the host prior to the arrival of the pathogen, and thereby reduce susceptibility to infection via cold Stress-Induced Disease Resistance (SIDR), a recently described phenomenon. This effect requires approximately 24 h post-cold before maximal resistance effect occurs, and is also transient in that the effect diminishes to a basal level within 48 h after exposure. Although the phenotypic responses to cold SIDR may be similar to those observed on ontogenically-resistant leaves, the effects of cold SIDR and ontogenic resistance are additive. Sufficient tools are now available for investigating the mechanistic basis of cold SIDR. While pathosystems involving obligate biotrophs complicate research on direct and indirect environmental effects on the pathogen, this requisite interaction also creates interesting systems to understand how the condition of the host may influence subsequent disease development. At the population level, the effects of repeated cold events have profound effects on the nature of epidemic progress and implications for management of grape powdery mildew. The objective in this review is to summarize our current knowledge regarding the indirect and consequential effects of low temperature on the development of grapevine powdery mildew.

show abstract

Effect of weather factors on the release of ascospores of Uncinula necator, the cause of grape powdery mildew, in the Bordeaux region

Cited by 24 publications

References 10 publications

Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

Measuring summer patterns of ascospore release by saltmarsh fungi

Cold Stress-Induced Disease Resistance (SIDR): indirect effects of low temperatures on host-pathogen interactions and disease progress in the grapevine powdery mildew pathosystem

Contact Info

Product

Resources

About