Effect of aerated compost tea on grapevine powdery mildew, botrytis bunch rot and microbial abundance on leaves

2012 ◽  
Vol 135 (4) ◽  
pp. 661-673 ◽  
Author(s):  
K. J. Evans ◽  
A. K. Palmer ◽  
D. A. Metcalf
Keyword(s):  
Powdery Mildew ◽  
Microbial Abundance ◽  
Compost Tea ◽  
Grapevine Powdery Mildew ◽  
Bunch Rot

Role of Overwintering Forms of Erysiphe necator in Epidemiology of Grapevine Powdery Mildew in Palestinian Vineyards

2014 ◽  
Vol 2 (1) ◽  
pp. 20-25
Author(s):  
Ruba Abuamsha ◽  
Hajaj Hajjeh ◽  
Mazen Salman
Keyword(s):  
Powdery Mildew ◽  
Temporal Evolution ◽  
Control Strategies ◽  
Temporal Distribution ◽  
Field Surveys ◽  
Sequence Characterized Amplified Region ◽  
Grapevine Powdery Mildew ◽  
Fungal Populations ◽  
Bud Breaking

The overwintering modes of E. necator were studied on Palestinian vineyards, through observations on the differentiation and maturation of cleistothecia and on the occurrence of flag-shoots (deriving from overwintering mycelium) in vineyards. Field surveys were carried out in 17 vineyards for the presence of Flag shoots and cleistothecia, both forms were not observed. Genetic structure and composition of E. necator populations were investigated by application of already available SCAR (Sequence Characterized Amplified Region) primers specific for the "flag-shoot" and "ascospore" biotypes. These primers were used to evaluate the dynamics of the spatial and temporal distribution of the two biotypes, into fungal populations present in 8 vineyards, with different cultivars and spray histories, in various Palestinian districts (Hebron, Bethlehem, Jerusalem, Ramallah, Jericho, Nablus, Jenin, Tulkarm). 397 samples were analyzed by the uses of the primer pairs UnE-UnF in PCR reactions. All samples were found to be of the ascospore biotypes. This finding shows that the “flag shoot” biotype, appears soon after bud breaking and disappears later, while the “ascospore” biotype is more frequently associated to later infections and bunches damages. Such information would be helpful to understand the reasons underlying possible temporal evolution of the pathogen's populations in vineyards, and can have important implications for powdery mildew rationale control strategies.

scholarly journals Genetic Structure and Aggressiveness of Erysiphe necator Populations during Grapevine Powdery Mildew Epidemics

2008 ◽  
Vol 74 (20) ◽  
pp. 6327-6332 ◽  
Author(s):  
Josselin Montarry ◽  
Philippe Cartolaro ◽  
François Delmotte ◽  
Jérôme Jolivet ◽  
Laetitia Willocquet
Keyword(s):  
Powdery Mildew ◽  
Latency Period ◽  
Growing Season ◽  
Spore Production ◽  
Erysiphe Necator ◽  
Genetic Groups ◽  
Grapevine Powdery Mildew ◽  
Temporal Differentiation ◽  
Group A ◽  
Group B

ABSTRACT Isolates of the causal ascomycete of grapevine powdery mildew, Erysiphe necator, correspond to two genetically differentiated groups (A and B) that coexist on the same host. This coexistence was analyzed by investigating temporal changes in the genetic and phenotypic structures of E. necator populations during three epidemics. Group A was present only at the start of the growing season, whereas group B was present throughout all three epidemics. Group A was less aggressive in terms of germination and infection efficiency but was more aggressive than group B in terms of the latency period, lesion diameter, and spore production. Our results are consistent with a temporal differentiation of niches, preventing recombination, and suggest an association between the disease level and the frequencies of genetic groups.

scholarly journals Effects of Sunlight Exposure on Grapevine Powdery Mildew Development

2012 ◽  
Vol 102 (9) ◽  
pp. 857-866 ◽  
Author(s):  
Craig N. Austin ◽  
Wayne F. Wilcox
Keyword(s):  
Powdery Mildew ◽  
Solar Radiation ◽  
Controlled Environment ◽  
Disease Development ◽  
Inhibitory Effects ◽  
Grapevine Powdery Mildew ◽  
Individual Experiment ◽  
Hyphal Formation ◽  
The Individual ◽  
Artificial Shading

Natural and artificially induced shade increased grapevine powdery mildew (Erysiphe necator) severity in the vineyard, with foliar disease severity 49 to 75% higher relative to leaves in full sun, depending on the level of natural shading experienced and the individual experiment. Cluster disease severities increased by 20 to 40% relative to those on check vines when ultraviolet (UV) radiation was filtered from sunlight reaching vines in artificial shading experiments. Surface temperatures of leaves in full sunlight averaged 5 to 8°C higher than those in natural shade, and in one experiment, filtering 80% of all wavelengths of solar radiation, including longer wavelengths responsible for heating irradiated tissues, increased disease more than filtering UV alone. In controlled environment experiments, UV-B radiation reduced germination of E. necator conidia and inhibited both colony establishment (hyphal formation and elongation) and maturity (latent period). Inhibitory effects of UV-B radiation were significantly greater at 30°C than at 20 or 25°C. Thus, sunlight appears to inhibit powdery mildew development through at least two mechanisms, i.e., (i) UV radiation's damaging effects on exposed conidia and thalli of the pathogen; and (ii) elevating temperatures of irradiated tissues to a level supraoptimal or inhibitory for pathogen development. Furthermore, these effects are synergistic at temperatures near the upper threshold for disease development.

Combining sanitation and disease modelling for control of grapevine powdery mildew

2012 ◽  
Vol 135 (4) ◽  
pp. 817-829 ◽  
Author(s):  
Tito Caffi ◽  
Sara Elisabetta Legler ◽  
Riccardo Bugiani ◽  
Vittorio Rossi
Keyword(s):  
Powdery Mildew ◽  
Disease Modelling ◽  
Grapevine Powdery Mildew

Release, germination, and pathogenicity of ascospores of Uncinula necator under controlled conditions

1998 ◽  
Vol 76 (5) ◽  
pp. 777-781 ◽  
Author(s):  
F Jailloux ◽  
T Thind ◽  
M Clerjeau
Keyword(s):  
Powdery Mildew ◽  
Vitis Vinifera ◽  
Storage Conditions ◽  
Vitis Vinifera L ◽  
Uncinula Necator ◽  
Grapevine Powdery Mildew ◽  
Germination Ability ◽  
Ascospore Release ◽  
Probable Role ◽  
Leaf Disks

A laboratory technique was standardized for studying the release, maturation, germination, and pathogenicity of ascospores of Uncinula necator (Schw.) Burr. Surface disinfestation and wetting of grape (Vitis vinifera L.) leaf disks bearing cleistothecia collected in the vineyard before incubation in a humid chamber for 48 h at 20°C were found essential for obtaining the release of ascospores (8 ascospores/cm2). Storage conditions involving periodic wetting treatments of cleistothecia at 5°C during 110 days were necessary to induce both ascospore release (80 ascospores/cm2) and germination ability (62%). The matured ascospores were pathogenic on healthy leaf disks at 20°C indicating their probable role as a primary inoculum source. This technique can be helpful in studying the inheritance of characteristics such as pathogenicity and fungicidal resistance.Key words: cleistothecia, ascospores, maturation, germination, pathogenicity, Uncinula necator, grapevine, powdery mildew.

Mode of action of milk and whey in the control of grapevine powdery mildew

2006 ◽  
Vol 35 (5) ◽  
pp. 487 ◽  
Author(s):  
P. Crisp ◽  
T. J. Wicks ◽  
G. Troup ◽  
E. S. Scott
Keyword(s):  
Powdery Mildew ◽  
Mode Of Action ◽  
Grapevine Powdery Mildew
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