Relative Susceptibility of Selected Apple Cultivars to Powdery Mildew Caused by Podosphaera leucotricha

2009 ◽  
Vol 10 (1) ◽  
pp. 3 ◽  
Author(s):  
Alan R. Biggs ◽  
Keith S. Yoder ◽  
David A. Rosenberger
Keyword(s):  
Powdery Mildew ◽  
Disease Incidence ◽  
Cultivar Differences ◽  
Susceptible Cultivar ◽  
Chronic Effect ◽  
Podosphaera Leucotricha ◽  
Yield Data ◽  
Golden Delicious ◽  
Regional Project ◽  
Apple Cultivars

Apple powdery mildew thrives during dry spring and summer weather wherever apples are grown. The fungus perennates in buds, making it difficult to control and, although it can cause fruit russet, it primarily causes losses due to its chronic effect on tree vigor and yield. Data were collected over several years from 1995 (23 entries) and 1999 (22 entries) plantings of new apple cultivars and selections established at multiple locations as part of regional project NE-183. The cultivars Golden Delicious and McIntosh were the standards in both plantings. Incidence of powdery mildew on leaves and fruit was observed and data were analyzed to determine differences due to location and cultivar. One of the two planting group analyses indicated the significance of cultivar differences due to location. In general, the cultivars Ginger Gold, Suncrisp, GoldRush, Crimson Crisp, and Delblush, and the selection CQR10T17 were the most susceptible, whereas the cultivars Gala Supreme, Enterprise, Zestar, September Wonder, Hampshire, and the selections NY 75414-1 and NY 79507-72 exhibited the lowest incidences of mildew. Pinova was the most highly susceptible cultivar to mildew on fruit in Virginia, followed by Crimson Crisp and the selection NY 65707-19. Percent leaf area with mildew was related to incidence of mildew on leaves; however, fruit symptoms were not significantly related to disease incidence or severity on the foliage. Accepted for publication 11 September 2009. Published 19 November 2009.

scholarly journals Apple powdery mildew caused by Podosphaera leucotricha: some aspects of disease management

2014 ◽  
Vol 20 (1-2) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Biological Control ◽  
Disease Management ◽  
Powdery Mildew ◽  
Chemical Control ◽  
Apple Cultivar ◽  
Apple Orchards ◽  
Cultivar Resistance ◽  
Podosphaera Leucotricha ◽  
Control Options ◽  
Apple Cultivars

Apple powdery mildew (Podoshphaera leucorticha) occurs wherever apples are grown. One of the most important fungal disease of apple which causing severe econimic loss on susceptible apple cultivars. This review focuses on the control of apple powdery mildew. The first part of the study provides details of novel aspects of non-chemical control approaches, including agronomic measures, mechanical and biological control options as well as essential features of apple cultivar resistance. After this, developments in chemical control options are described sperately for integrated and organic apple orchards.

scholarly journals Evaluation of reactions of commercial and autochthonous apple cultivars to common diseases in Serbia under natural infection

2017 ◽  
Vol 32 (3-4) ◽  
pp. 157-172 ◽  
Author(s):  
Jelica Balaz ◽  
Vladislav Ognjanov ◽  
Zoran Keserovic ◽  
Aleksandra Sucur ◽  
Jaap Janse ◽  
...  
Keyword(s):  
Erwinia Amylovora ◽  
Venturia Inaequalis ◽  
Natural Infection ◽  
Gold Rush ◽  
Podosphaera Leucotricha ◽  
The Czech Republic ◽  
Golden Delicious ◽  
The Usa ◽  
Apple Cultivars ◽  
Moderately Resistant

This study presents the results of a multiple-year evaluation (1991-1996; 2005-2007) of susceptibility of more than 100 apple cultivars to Venturia inaequalis, Podosphaera leucotricha and Erwinia amylovora under agroecological conditions existing in Serbia. Some of the most popular cultivars were found highly susceptible to V. inaequalis (Cripps Pink, Mutsu, Gloster 69, Wellspur); while Golden Delicious, Richared, Gala, Cacanska pozna, Cadel and Jonagold were susceptible; Idared, Granny Smith and Jonathan moderately susceptible; Lord Lamburne and London Pepping, as well as several autochthonous cultivars were moderately resistant; and a group of resistant cultivars included Prima, Priscilla, Williams Pride, Dayton, Enterprise, Gold Rush, Golden Orange, many of the Re-cultivars (Germany), as well as Baujade, Selena, Duk?t, Produkta, Topaz, some older cvs. (Worcester Pearmain, Merton Worcester, James Grieve, Akane, Astilish, Astrachan Red and Discovery), some Co-op selections (USA) and NS hybrids (Serbia). Regarding powdery mildew, Idared and Jonathan were highly susceptible; Gala, Akane, Jonagold, Priscilla, Mutsu, Cacanska pozna, Golden Delicious, Granny Smith, Cadel and GoldRush were susceptible; Wellspur, Astrachan Red, Richared, Jonadel, Dayton and several autochthonous cultivars were moderately susceptible; Lord Lamburne, Astlisch, Prima, Champagne Reinette, Discovery and many autochthonous cultivars were moderately resistant; while most Re-cvs. (Germany), several cultivars from the Czech Republic, some selections from the USA and UK and most NS hybrids (Serbia) were resistant. Also, some cultivars showed variable susceptibility depending on location (Williams Pride, Gloster 69, Baujade and Produkta). E. amylovora was observed only in 2007 and at relatively low intensity (up to 12% infection). The highest disease severity was observed on cv. Elstar, then Granny Smith, Idared and Jonagored; while the lowest was found on Red Chief and Hapke apple trees.

scholarly journals Apple cultivars bred in Holovousy. Part 1 – Characteristics of the orchard

2013 ◽  
Vol 40 (No. 1) ◽  
pp. 8-15 ◽  
Author(s):  
J. Blažek ◽  
J. Křelinová
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Comparative Study ◽  
Sectional Area ◽  
Harvest Time ◽  
Cross Sectional ◽  
The Czech Republic ◽  
Golden Delicious ◽  
Apple Cultivars ◽  
The Mean

 Twenty-one standard apple cultivars bred in Holovousy and registered in the Czech Republic during 1994–2011 were included in a comparative study. Their tree parameters and yields were evaluated from 2004 till 2011 in a comparison to cvs Golden Delicious and Jonagold within experimental orchards planted on M 9 rootstock using a tree spacing of 4 × 1 m. The cultivars mutually differed in the mean term of flowering starting up to 6 days. The harvest time of 5 summer cultivars covered the harvest season from July 14 till the end of August. The remaining cultivars were storable, and on average, their harvest started between the September 8(Nabella) and November 8 (Rubimeg). Cvs Resista, Selena and Vysočina were evaluated as totally resistant to scab and 5 other cultivars were distinguished by very low susceptibility to the disease. In the case of powdery mildew this desirable level of tolerance was observed on 7 cultivars. The most vigorous according to trunk cross-sectional area was cv. Mivine, whereas the weakest growing cv. Selena was 52% smaller in this parameter. Significant differences among cultivars were also found in the case of yield precocity. In total, the most productive in this study was cv. Clijo, with mean annual harvest equal to 44.3 t/ha. The lowest level of annual harvest (25.6 t/ha) gave cv. Selena, but its crop efficiency was one of the highest.

scholarly journals Development and ultrastructure observations of secondary hyphae of Podosphaera leucotricha on apple cultivars of varying susceptibility to powdery mildew

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 425-428
Author(s):  
E. Rakhimova
Keyword(s):  
Electron Microscopy ◽  
Powdery Mildew ◽  
Light And Electron Microscopy ◽  
Dense Material ◽  
Podosphaera Leucotricha ◽  
Powdery Mildew Fungus ◽  
Full Complement ◽  
Apple Cultivars ◽  
Host Parasite

The development and ultrastructure feature of secondary hyphae of Podosphaera leucotricha were studied using light and electron microscopy. The percentage of development and length of secondary hyphae, differed in compatible and incompatible combinations. In compatible host-parasite combinations, hyphal cells of powdery mildew fungus contained a full complement of fungal organelles. There were differences of hyphal ultrastructure in compatible and incompatible host-parasite combinations, the main one was the appearance of dense material inside the nucleus, in the cytoplasm, and a few mitochondria.

Susceptibility of apple cultivars to apple scab and powdery mildew in Victoria, Australia

1998 ◽  
Vol 38 (6) ◽  
pp. 625 ◽  
Author(s):  
W. S. Washington ◽  
O. N. Villalta ◽  
J. Ingram ◽  
D. Bardon
Keyword(s):  
Powdery Mildew ◽  
Venturia Inaequalis ◽  
Natural Infection ◽  
Apple Scab ◽  
Podosphaera Leucotricha ◽  
Commercial Cultivars ◽  
Apple Cultivars ◽  
High Level

Summary. Twenty apple cultivars were assessed over 3 seasons for their susceptibility to natural infection with scab (caused by Venturia inaequalis) and powdery mildew (caused by Podosphaera leucotricha). It was evident that a number of important commercial cultivars are highly susceptible to leaf scab (average incidence of leaf scab: Pink Lady, 40.2% of leaves; Lady William, 37.1%; Braeburn, 20.0%; and New Jonagold, 18.7%) and powdery mildew (average incidence of leaf mildew: New Jonagold, 23.0%; Pink Lady, 17.8%). There was a high level of resistance to leaf scab in the cultivars Florina-Quérina, Redfree and Jonafree (all less than 1% incidence on leaves) and to powdery mildew in the cultivar Earlidel (no infection observed). The cultivars Jonathan, Bonza and Red Elstar showed a useful level of resistance to scab (average incidence of leaf scab between 1.6 and 3.2%), while the cultivars Red Fuji, HiEarly and Redfree all showed some resistance to powdery mildew (average incidence of mildew between 2.6 and 5.9%). Observations made on the low and variable numbers of fruit produced by some trees in their third year after planting showed that Pink Lady and Lady William were highly susceptible to fruit scab (67.6 or 57.6% scabbed fruit respectively). Twig infection by scab was also observed on shoots of the current season’s growth of Pink Lady.

scholarly journals Field susceptibility of 13 scab-resistant apple cultivars to apple powdery mildew [Podosphaera leucotricha (Ell. et Ev.) Salmon]

2013 ◽  
Vol 40 (1-2) ◽  
pp. 87-98
Author(s):  
Zbigniew Borecki
Keyword(s):  
Powdery Mildew ◽  
Chemical Control ◽  
Podosphaera Leucotricha ◽  
Apple Trees ◽  
Complete Field ◽  
Apple Cultivars ◽  
Disease Pressure ◽  
Moderate Susceptibility

Field susceptibility of 13 scab-resistant apple cultivars to apple powdery mildew was evaluated in 1983-1986. Four groups of susceptibility were distinguished. None of the 13 tested scab-resistant apple trees exhibited complete field immunity to apple powdery mildew. Two cultivars, 'Prima' and 'Primula', were practically resistant. 'Liberty' and two numbered selections, NY-140-9 and NY-158-2, belonged to the group of lower susceptibility. Moderate susceptibility was shown by: 'Novamac', 'Freedom', 'Gavin', 'Prima' and 'Florina'. The group of apple trees most susceptible to <i>Podosphaera leucotricha</i> included: 'Macfree', 'Priscilla' and 'Nova Easygro'. It is not necessary to use chemical sprays to control powdery mildew on 'Prima' and 'Primula'. A reduced spraying program may be recommended only under high disease pressure on less susceptible apple cultivars. A regular spray schedule is needed on moderately susceptible apple trees, but improved chemical control is necessary on the most susceptible ones.

scholarly journals Apple powdery mildew caused by Podosphaera leucotricha: some aspects of biology

2013 ◽  
Vol 19 (3-4) ◽  
Author(s):  
I. Holb
Keyword(s):  
Powdery Mildew ◽  
Geographical Distribution ◽  
Causal Agent ◽  
Host Susceptibility ◽  
Podosphaera Leucotricha ◽  
Disease Cycle ◽  
The Past ◽  
The World ◽  
Apple Cultivars ◽  
Resistance Durability

Apple powdery mildew (Podoshphaera leucorticha) occurs wherever apples are grown. One of the most important fungal disease of apple which causing severe econimic loss on susceptible apple cultivars. Biology of the pathogen is widely investigated all over the world in the past 100 years. In this review, a summary from this enormous research is made for biology of apple powdery mildew in the following aspects: geographical distribution, morphology, taxonomy of the causal agent, symptoms, host susceptibility, resistance durability and disease cycle.

Optimizing Use of DMI Fungicides for Management of Apple Powdery Mildew Caused by Podosphaera leucotricha in New York State

Plant Disease ◽  
2021 ◽  
Author(s):  
David Strickland ◽  
Sara M. Villani ◽  
Kerik Cox
Keyword(s):  
New York ◽  
Powdery Mildew ◽  
Disease Control ◽  
Disease Incidence ◽  
New York State ◽  
Optimal Timing ◽  
Fresh Market ◽  
Podosphaera Leucotricha ◽  
York State ◽  
Dmi Fungicides

Powdery mildew, caused by the ascomycete Podosphaera leucotricha, is an endemic disease found wherever apples are grown that negatively impacts both tree vigor and fresh market yield. In the absence of durable host resistance, chemical management is the primary means of disease control. Demethylation inhibitor (DMI) fungicides are widely used to manage apple powdery mildew, but members within this fungicide class have been observed to differ in efficacy with respect to disease control. Moreover, debate exists as to the optimal timing of DMI fungicide applications for management of apple powdery mildew. In this regard, the goal of this study was to determine the best-use practices for DMI fungicides to manage apple powdery mildew in New York State. Multi-year trials were conducted to evaluate the potential differential efficacy performance of four common DMI fungicides, as well as additional trials to assess optimal application timing. In all years, we observed that treatments of flutriafol and myclobutanil consistently had the lowest incidences of powdery mildew compared to difenoconazole and fenbuconazole. In the 2018 and 2021 trials, the newly registered mefentrifluconazole was more comparable to the difenoconazole program with respect to powdery mildew disease incidence. We hypothesize that differences in DMI efficacy may be due to each fungicides’ water solubility and lipophilicity characteristics, and thus their ability to move systemically in the host or more easily penetrate the surface of germinating conidia. Applications timed between petal fall and first cover resulted in the lowest incidence of powdery mildew on terminal leaves of apple shoots compared to applications timed prior to petal fall. These observations are contrary to previous studies conducted in regions with differing climates. We also found that the incidence of secondary powdery mildew observed two weeks after petal fall was influenced by applications of DMI fungicides during the previous season. For example, management programs consisting of applications of flutriafol or myclobutanil in the prior season tended to have lower incidence of apple powdery in the following spring, presumably owing to reductions in overwintering inoculum. Despite reports of DMI resistance in other apple pathosystems, the DMI fungicide class is still relevant for the successful management of apple powdery mildew in New York State.

scholarly journals Effect of pruning on disease incidence of apple scab and powdery mildew in integrated and organic apple production

2005 ◽  
Vol 11 (1) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Powdery Mildew ◽  
Production System ◽  
Production Systems ◽  
Venturia Inaequalis ◽  
Disease Incidence ◽  
Apple Scab ◽  
Organic Production ◽  
Environmentally Benign ◽  
Apple Cultivars ◽  
Apple Production

In a three-year study, the effect of two winter pruning treatments (strong and weak) on apple scab (Venturia inaequalis) and powdery mildew (Podosphaera leucotricha) was evaluated on six apple cultivars (`Rewena', `Elstar', 'Liberty', 'Gala', 'Pilot' and `Jonica') in two environmentally-benign apple production systems (integrated and organic). Results on apple scab showed that compared to the integrated production system, the pathogen caused significantly more infection on the leaves of cvs. `Elstar', 'Gala' and `Jonica' in the organic production system. The effect of pruning treatments on apple scab was mainly detectable on the cultivars susceptible to the disease such as cvs. 'Gala' and `Jonica'. The weak pruning correlated with a higher level of apple scab infection than the strong pruning, especially in the organic production system. Primary mildew infection was very low in both protection systems (below 2 %), therefore, effect of pruning on primary mildew infection could not be analysed. Low secondary mildew incidence was detected in the organically treated orchard part; however, incidence of powdery mildew was significantly higher (P> 0.05) on cvs. 'Elstar', 'Pilot' and `Jonica' in the integrated orchard part compared to cvs. 'Gala', 'Rewena' and 'Liberty'. The highest incidence of mildew was on cv. 'Elstar'. Pruning had very low effect on incidence of secondary mildew infection on leaves.

A novel technique for evaluation of apple (Malus × domestica Borkh.) cultivars for susceptibility to powdery mildew

2001 ◽  
Vol 81 (2) ◽  
pp. 289-296 ◽  
Author(s):  
P. L. Sholberg ◽  
W. D. Lane ◽  
P. Haag ◽  
K. Bedford ◽  
L. Lashuk
Keyword(s):  
Powdery Mildew ◽  
Research Centre ◽  
Cultivar Resistance ◽  
Podosphaera Leucotricha ◽  
Malus Domestica Borkh ◽  
Novel Technique ◽  
Food Research ◽  
The Pacific ◽  
Apple Cultivars ◽  
Breeding Selection

A technique for the evaluation of apple cultivars for susceptibility to powdery mildew caused by Podosphaera leucotricha (Ell. & Ev.) E. S. Salmon (anamorph Oidium farinosum Cooke) was tested at the Pacific Agri-Food research Centre (PARC), Summerland, BC. Shoots of test cultivars [Braeburn, Creston, Elstar, Empire, Fuji strain BC2, Gala strain Royal, Jonagold, McIntosh, Delicious red strain Bisbee, Shamrock, Silken, Sunrise, and one breeding selection (11w-17-85)], approximately 6 cm in length, were grafted on to branches of mature Jonagold trees in the spring and evaluated in the summer of the same year and in subsequent years after growth on the host tree. Incidence and severity of powdery mildew were evaluated in 1994, 1995, 1997, and 1998. They were not evaluated in 1996 because approximately half the grafts from the previous year did not grow and had to be replaced. The highest incidence of powdery mildew averaged 84% for Gala, compared with only 15% for Bisbee Delicious with the lowest incidence. Gala had the highest number of P. leucotricha conidia per cm2 of leaf area (4.9 × 104) compared to Bisbee Delicious (1.2 × 104). Some of the grafted cultivars were also evaluated for primary powdery mildew and fruit russetting in 1998 after the growth for three seasons. Jonagold had the highest numbers of primary infections and russetted fruit. Key words: Podosphaera leucotricha, breeding, cultivar resistance, pest management

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