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• Apple powdery mildew caused by Podosphaera leucotricha: some important features of biology and epidemiology

  45-51.

  I. J. Holb

  Views:

  340

  In this review, some important features of biology and epidemiology are summarised for apple powdery mildew (Podosphaera leucotricha). In the first part of the review, the geographical distribution or the pathogen are discussed, then the morphology and taxonomy of the causal organism are described. Disease symptoms or apple powdery mildew are also shown and then host susceptibility/resistance is discussed in relation to durability of resistance. In the second part of this review, the general disease cycle of powdery mildew on apple are demonstrated and some basic features of powdery mildew epidemiology (such response of the pathogen to temperature, relative humidity, and rain as well as spore production, spore dispersal, diurnal patterns and temporal dynamics of the pathogen/disease) are also given on apple host.

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

  29-33.

  I. J. Holb

  Views:

  527

  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.

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

  57-61.

  I. J. Holb

  Views:

  230

  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.

• Pruning and incidences of diseases and pests in environmentally oriented apple growing systems: some aspects

  24-29.

  I. J. Holb

  I. Gonda

  K. Bitskey

  Views:

  223

  In Hungary, fruit growers are increasingly interested in environmentally oriented growing methods, such as organic and integrated systems. The main factor in creating such systems is the establishment of a system of cultivar-pruning-plant protection based on production technology. Therefore, our aim was to examine the susceptibility of apple cultivars to diseases and pests and the effect of pruning technique on diseases and pests in organic and integrated growing systems.

  Two pathogens (Venturia inaequalis, Podosphaera leucotricha) and two pests (Leueoptera malifoliella, Pannonychus ulmi) were observed in organic and integrated systems under "strong" and "weak" pruning techniques. Our results showed that, compared to integrated production, the pathogens and pests infected the trees more in the organic system. The pruning technique affected mainly the cultivars susceptible to diseases and pests. In general, the "weak" pruning technique correlated with a higher level of damage caused by diseases and pests than the "strong" pruning technique, especially in the organic growing system. The reason that techniques should be carefully chosen is that shoots grow faster and more vigorously after employing the "strong" pruning technique. This supports a better preservation of the trees, as a result of reduced susceptibility of plant tissues to diseases and pests.

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

  19-23.

  I. Holb

  Views:

  348

  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.

• Effect of reduced spray programmes on incidences of apple scab, powdery mildew and codling moth damage in environmentally freindly apple production systems

  75-78.

  I. J. Holb

  M. Fazekas

  F. Abonyi

  P. Lakatos

  S. Thurzó

  J. Nyéki

  Z. Szabó

  J. Kruppa

  B. Balla

  Views:

  665

  Still a large amount of pesticides and spary applications are used in environmentally friendly fruit production systems; therefore, the aim of our study was first to test the in vitro effeicacy of some fungicides against a key apple disease (apple scab), and secondly to evaulate the effectiveness of reduced spray programmes against apple scab, powdery mildew and coding moth in integrated and organic apple orchards. In vitro efficacy of 7 fungicides (Champion 50 WP, Kocide 2000, Nordox 75 WG, Olajos rézkén, Kumulus S, Rézkén, Rézoxiklorid) and another 6 fungicides (Score 25 EC, Efuzin 500 SC, Systane, Folicur Solo, Zato Plusz, Rovral) approved in organic and integrated production systems, respectively, were tested against apple scab. Altogether four spray programmes were performed i) standard integrated: sprays followed by forecasting systems during the season, ii) reduced integrated: sprays followed by forecasting systems but only 75% of the spray numbers used during the season-long spray programme, iii) standard oragnic: sprays applied every 7–14 days during the season and iv) reduced organic: 60% of the spray numbers used during the season-long spray programme. In vitro results showed that fungicides (with active ingredients of copper and sulphur) applied in organic production showed relatively high percent growth capacity of the apple scab fungus. Rézkén showed the highest and Kumilus S the lowest efficacy against apple scab. Fungicides applied in integrated production showed relatively low percent growth capacity of the apple scab fungus. Score 25 EC showed the highest and Rovral the lowest efficacy against apple scab. Field study showed that reduced spray programmes did not increase significantly scab incidence in the integrated field. However, scab incidence increased significanly (above 30%) in the reduced spray programme for the organic orchard.Mildew incidence was low (below 5%) in both integrated and organic spray programmes. Mildew incidence on both shoots and fruits increased significanly in the reduced spray programme for the organic orchard. Incidence of codling moth damage was affected the most by standard vs. reduced spray programmes. Though incidence remained below 10% in the integrated plots, the incidence was significantly higher in the reduced spray programme compared to the standard programme. Similar results were obtained for organic spary programmes, but the incidence was 10 times higher and the differences among the two programmes were larger.,