Host range of a powdery mildew (Erysiphe orontii) on tomato

2001 ◽  
Vol 81 (1) ◽  
pp. 179-182 ◽  
Author(s):  
R. S. Utkhede ◽  
C. A. Koch ◽  
J. G. Menzies ◽  
D. L. Ehret
Keyword(s):  
Powdery Mildew ◽  
Host Range ◽  
Host Resistance ◽  
Morning Glory ◽  
Breeding Programs ◽  
Wild Buckwheat ◽  
Greenhouse Tomato ◽  
Tomato Cultivars ◽  
Fraser Valley ◽  
Powdery Mildew Infection

A powdery mildew disease of greenhouse tomato first appeared in the Fraser Valley of British Columbia in 1995. The causal agent was identified as Erysiphe orontii. Host range studies were conducted using uniform levels of inoculum of the pathogen under greenhouse conditions. Of 26 tomato cultivars inoculated, cv. DRW4409F1 had the least powdery mildew infection. Twenty-five of the 26 tomato cultivars tested, as well as eggplant cv. Early Long Purple, nightshade and tomatillo, were susceptible to E. orontii. Tobacco and potato (cv. Epicure) had slight infection. Cultivars of pepper, potato, corn, strawberry, raspberry, bean, feverfew, borage, delphinum, petunia, impatiens, gazania, morning glory, zinnia, african daisy, cosmos, wild buckwheat, curled dock, and knotweed were not susceptible to E. orontii. This study indicates that resistance to powdery mildew of tomato is available and should be explored in breeding programs to develop powdery mildew-resistant cultivars for the greenhouse industry. Key words: Host resistance, Lycopersicon esculentum, powdery mildew, Solanaceae

scholarly journals Yield and Russeting of Greenhouse Tomato as Influenced by Leaf-to-fruit Ratio and Relative Humidity

HortScience ◽  
2007 ◽  
Vol 42 (3) ◽  
pp. 503-507 ◽  
Author(s):  
Dominique-André Demers ◽  
Martine Dorais ◽  
Athanasios P. Papadopoulos
Keyword(s):  
Relative Humidity ◽  
Lycopersicon Esculentum ◽  
Progressive Increase ◽  
Early Spring ◽  
Breeding Programs ◽  
Greenhouse Tomato ◽  
High Incidence ◽  
Number Of Leaves ◽  
Tomato Cultivars ◽  
Very High

Three experiments were conducted in greenhouses 1) to determine the optimal leaf-to-fruit ratio for minimizing the incidence of russeting (miniature cuticle cracks on fruit) while optimizing fruit yield of greenhouse tomato (Lycopersicon esculentum Mill.) and 2) to investigate the effect of day/night relative humidity (RH) regimens on the development of russeting. Leaf-to-fruit ratio treatments (0.5–2.0) were achieved by varying the number of fruit (two to six fruit) per cluster and the number of leaves (two to four leaves) between clusters. In one experiment, plants were also subjected to either high day/low night or low day/high night RH regimens (low RH, 60% to 70%; high RH, 85% to 95%). Results showed that russeting of greenhouse tomato was mostly influenced by the number of fruit per cluster (total fruit load), and very little by the number of leaves between clusters. In general, decreasing the number of fruit per cluster resulted in a progressive increase in the occurrence of russeting. Furthermore, as the number of fruit per cluster decreased, the percentage of fruit with no russeting and with little russeting decreased whereas the percentage of fruit with the more severe russeting increased (except for the summer). For beefsteak cultivars Trust and Rapsodie grown under southwestern Ontario conditions, the best pruning practices for minimizing russeting and optimizing yield was to prune clusters to three fruit in early spring and late fall, to four fruit during spring and fall, and to five fruit during the summer, with three leaves between clusters all year long. In the current study, no significant effect of day/night RH regimens on fruit russeting was observed. Of the cultivars used, Rz 74/56 was less sensitive to russeting than ‘Trust’, whereas ‘Rapsodie’ was not different from the two other cultivars. However, all three cultivars had a very high incidence of russeting (>65% of fruit affected), and none should be regarded as russeting resistant. Breeding programs and genetic investigations with the objective of developing greenhouse tomato cultivars resistant to russeting are needed.

scholarly journals Evaluation of sainfoin accessions exposed to powdery mildew disease at four locations in Iran

2021 ◽  
Vol 9 (1) ◽  
pp. 97-108
Author(s):  
Mohammad Ali Alizadeh ◽  
Ali Ashraf Jafari ◽  
Karam Sepahvand ◽  
Saied Davazdahemami ◽  
Mohammad Rahim Moeini ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Dry Matter ◽  
Severity Index ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Breeding Programs ◽  
Dry Matter Digestibility ◽  
Yield And Quality ◽  
Water Soluble Carbohydrate ◽  
Powdery Mildew Infection

In order to evaluate resistance of sainfoin (Onobrychis viciifolia) to powdery mildew, seeds of 19 accessions were collected from different parts of Iran and sown at 4 locations, i.e. Kheirabad, Khoramabad, Semirom and Tabriz, in 2014. Accessions were evaluated for powdery mildew severity index (DSI), forage dry matter yield (DM), dry matter digestibility (DMD) and crude protein (CP) and water soluble carbohydrate (WSC) concentrations over 4 years. Based on Duncan’s test, accessions 15353 and 3001 showed disease severity index lower than 25% and were nominated as resistant to powdery mildew. Accessions Oshnavieh and Polycross were considered semi-resistant due to their DSI ranging from 25 to 50%. Other accessions were considered susceptible because their DSI was higher than 50%. The resistant accessions (15353 and 3001) with average yields of 3,341 and 3,304 kg DM/ha were ranked as having high DM production, in addition to displaying high DMD plus high CP and WSC concentrations. Severity of powdery mildew infection was linked negatively with all 3 quality traits, i.e. DMD and CP and WSC concentrations. According to Eberhart/Russell regression results, stability of accessions 3001 and 15353 for DSI and DM yield was confirmed across 4 locations. We recommend the use of accessions 3001 and 15353 in future breeding programs to increase resistance to powdery mildew, while at least maintaining yield and quality attributes. Evaluation of other sources of sainfoin germplasm should continue to identify further resistant accessions.

Occurrence of New Powdery Mildew on Greenhouse Tomato Cultivars

2001 ◽  
Vol 67 (4) ◽  
pp. 294-298 ◽  
Author(s):  
Yoshinori MATSUDA ◽  
Koichi KASHIMOTO ◽  
Yoshihiro TAKIKAWA ◽  
Rika AIKAMI ◽  
Teruo NONOMURA ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Greenhouse Tomato ◽  
Tomato Cultivars

scholarly journals Golovinomyces longipes (Noordel. & Loer.) L. Kiss on Matricaria chamomilla L.: another host range expansion

2021 ◽  
Author(s):  
M. Götz ◽  
U. Braun
Keyword(s):  
Sequence Analysis ◽  
Powdery Mildew ◽  
Host Range ◽  
Dna Sequence ◽  
Range Expansion ◽  
Matricaria Chamomilla ◽  
Important Family ◽  
The Past ◽  
Morphological Studies ◽  
Host Range Expansion

AbstractGolovinomyces longipes is a widespread powdery mildew on Solanaceae (Nicotiana, Petunia and Solanum spp.). In the past, it has been reported only once on Verbena (Verbenaceae), a non-solanaceaous host. Recently, this powdery mildew has been found on the composite Matricaria chamomilla. The identification of the powdery mildew species on this unusual host has been proved by morphological studies and DNA sequence analysis. Both datasets coincide with the characteristic data for G. longipes on Solanaceae. First inoculation experiments with further composites resulted in an infection of Brachyscome hybrid ‘Surdaisy’. To our knowledge, this is the first report of G. lonigpes on hosts belonging to the important family of Asteraceae and an additional proof of the broader host range of G. longipes beyond the Solanaceae.

scholarly journals Further Support of Conspecificity of Oak and Mango Powdery Mildew and First Report of Erysiphe quercicola and Erysiphe alphitoides on Mango in Mainland Europe

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1086-1093 ◽  
Author(s):  
Marie-Laure Desprez-Loustau ◽  
Marie Massot ◽  
Nicolas Feau ◽  
Tania Fort ◽  
Antonio de Vicente ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Host Range ◽  
Molecular Mechanisms ◽  
Single Copy ◽  
Broad Host Range ◽  
First Report ◽  
Erysiphe Quercicola ◽  
Powdery Mildews ◽  
Mango Leaves ◽  
Practical Implications

Mango leaves and inflorescences infected by powdery mildew in southern Spain were analyzed using multigene sequencing (ITS + 4 single-copy coding genes) to identify the causal agent. Erysiphe quercicola was detected in 97% out of 140 samples, collected in six different orchards in the Malaga region. Among these, a small proportion also yielded E. alphitoides (8% of all samples) and E. alphitoides was found alone in 3% of samples. A phylogenetic approach was completed by cross inoculations between oak and mango, which led to typical symptoms, supporting the conspecificity of oak and mango powdery mildews. To our knowledge, this is the first report of E. quercicola and E. alphitoides causing powdery mildew on mango trees in mainland Spain, and thus mainland Europe, based on unequivocal phylogenetic and biological evidence. Our study thus confirmed the broad host range of both E. quercicola and E. alphitoides. These results have practical implications in terms of the demonstrated ability for host range expansion in powdery mildews. They also open interesting prospects to the elucidation of molecular mechanisms underlying the ability to infect single versus multiple and unrelated host plants since these two closely related powdery mildew species belong to a small clade with both generalist and specialist powdery mildews.

The ultrastructure of M1-a-mediated resistance to powdery mildew infection in barley

1975 ◽  
Vol 53 (22) ◽  
pp. 2589-2597 ◽  
Author(s):  
H. H. Edwards
Keyword(s):  
Powdery Mildew ◽  
Host Cell ◽  
Electron Density ◽  
Epidermal Cells ◽  
Dense Material ◽  
Ultrastructural Changes ◽  
Electron Dense Material ◽  
Host Cytoplasm ◽  
Powdery Mildew Infection ◽  
Cell Protoplast

M1-a-mediated resistance in barley to invasion by the CR3 race of Erysiphe graminis f. sp. hordei does not occur in every host cell with the same speed and severity. In some cells ultrastructural changes within the host cell as a result of resistance will occur within 24 h after inoculation, whereas in other cells these changes may take up to 72 h. In some cells the ultrastructural changes are so drastic that they give the appearance of a hypersensitive death of the host cell, whereas in other cells the changes are very slight. In any case, at the end of these changes the fungus ceases growth. The ultrastructural changes occur in penetrated host epidermal cells as well as non-infected adjacent epidermal and mesophyll cells.The following ultrastructural changes have been observed: (1) an electron-dense material which occurs either free in the vacuole or adhering to the tonoplast (the material is granular or in large clumps); (2) an increased electron density of the host cytoplasm and nucleus; (3) a breakdown of the tonoplast so that the cytoplasmic constituents become dispersed throughout the cell lumen; and (4) the deposition of papillar-like material in areas other than the penetration site. The first three changes take place within the host cell protoplasts and are directly attributable to the gene M1-a. These changes are typical of stress or incompatibility responses and thus M1-a appears to trigger a generalized incompatibility response in the presence of race CR3. The papillar-like material occurs outside the host cell protoplast in the same manner as the papilla and probably is not directly attributable to M1-a.

Changes in photosynthesis of Lycopersicon spp. plants induced by tomato powdery mildew infection in combination with heat shock pre-treatment

2010 ◽  
Vol 74 (3-4) ◽  
pp. 205-213 ◽  
Author(s):  
Jitka Prokopová ◽  
Barbora Mieslerová ◽  
Vladimíra Hlaváčková ◽  
Jan Hlavinka ◽  
Aleš Lebeda ◽  
...  
Keyword(s):  
Heat Shock ◽  
Powdery Mildew ◽  
Tomato Powdery Mildew ◽  
Pre Treatment ◽  
Powdery Mildew Infection

Identification of Resistance to Powdery Mildew in Publicly Available Male Hop Germplasm

2018 ◽  
Vol 19 (3) ◽  
pp. 258-264
Author(s):  
David H. Gent ◽  
Briana J. Claassen ◽  
Megan C. Twomey ◽  
Sierra N. Wolfenbarger
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
Western United States ◽  
R Genes ◽  
Sources Of Resistance ◽  
Department Of Agriculture ◽  
Breeding Programs ◽  
The Pacific ◽  
The U.S

Powdery mildew (caused by Podosphaera macularis) is one of the most important diseases of hop in the western United States. Strains of the fungus virulent on cultivars possessing the resistance factor termed R6 and the cultivar Cascade have become widespread in the Pacific Northwestern United States, the primary hop producing region in the country, rendering most cultivars grown susceptible to the disease at some level. In an effort to identify potential sources of resistance in extant germplasm, 136 male accessions of hop contained in the U.S. Department of Agriculture collection were screened under controlled conditions. Iterative inoculations with three isolates of P. macularis with varying race identified 23 (16.9%) accessions with apparent resistance to all known races of the pathogen present in the Pacific Northwest. Of the 23 accessions, 12 were resistant when inoculated with three additional isolates obtained from Europe that possess novel virulences. The nature of resistance in these individuals is unclear but does not appear to be based on known R genes. Identification of possible novel sources of resistance to powdery mildew will be useful to hop breeding programs in the western United States and elsewhere.

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