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  • Cracking susceptibility evaluation of some stone fruit species (Sour cherries – Prunus cerasus L.; Sweet cherries – Prunus avium and European plums – Prunus domestica L.) grown in Hungary
    45-54.
    Views:
    249

    The rain induced fruit cracking is a big, serious problem especially for sweet cherry growers but in some year growers of other stone fruit species had also problem with fruit cracking caused by too much and heavy rainfalls in the ripening and harvesting season. Cracked stone fruits can be easily infected by different diseases like Monillinia sp. Cracked and infected fruits can not be transported for long distance and using for preservation, they lost their market value by the destroyed fruit quality. It was decided to make a research work to determine the rain fruit cracking susceptibility of few stone fruit species (sour cherries, sweet cherries and European plums). Fruit cracking tests were occurred under laboratory conditions on the most common cultivars grown in Hungary. Furthermore we tried to find correlation between the fruit cracking and some fruit quality parameters (fruit size; total sugar content, fruit flesh firmness).

    Our conclusions are the followings:
    Sour cherries: There were found differences in the cracking ratio and the cracking dynamics of the tested sour cherry varieties when they were immersed in distillated water for 24 hours. Based on cracking test results under laboratory condition (immersing in distillated water) we made the grouping by cracking susceptibility of sour cherry varieties. Tested cultivars were divided three groups: very susceptible; susceptible; moderately susceptible (tolerant). Groups with varieties are: Very susceptible - ’Maliga emléke’, ’Piramis’, ’Érdi jubileum’,’Érdi nagygyümölcsû’ and ’Meteor korai; Susceptible (Sensitive) – ’Érdi bôtermô’, ’Pándy’ and Cigány 59. Moderately susceptible (tolerant) – ‘Éva’ and ‘Petri’as new rereleases. The most of tested sour cherry varieties are in agreement with the literature (Apostol, 2003) and four of them (’Maliga emléke’, ’Pándy 279’, ‘Éva’ and ‘Petri’) had higher average fruit weight than was mentioned in the literature (Apostol, 2003). Our fruit cracking results are in agreement with Zelinski’s (1964) and Christensen’s (1975) conclusions that there is no close relationship between fruit size and rain induced fruit cracking tendency. We found significant differences between the sugar content of tested cultivars. In contrast of Verner & Blodget (1931) our results confirm Tucker’s opinion that the sugar content is not correlation with the cracking tendency of cherry fruits (Tucker, 1934). Fruits firmness (elasticity) was measured by destructive method when juice was coming out from fruits. There were found big differences of fruit firmness and skin strength of observed cultivars. Our results are only partly agreement with Christensen’s (1996) opinion that cherry cultivars with firmer fruits are more prone to fruit cracking than softer ones. By this was seemingly we did not found close relationship between the fruit firmness and the cracking tendency of sour cherry fruits. We found that during fruits immersing in distillated water the fruit weight was increasing due to the absorbed water. Our opinion is that there is no close relationship between the scale of fruit cracking and the quantity of absorbed water. By results presented above we our opinion is that no very close relationship between the fruit cracking of sour cherries and the observed parameters (fruit size, fruit firmness, sugar content, amount of absorbed water) maybe other varietal effects and physiological characters (fruit skin structural parameters) play more important role in the fruit cracking mechanism of cherries.

    Sweet cherries: Similarly to sour cherries in the case of sweet cherries we also did not find close relationship between observed fruit parameters and cracking index. It was differences in the cracking ratio and the cracking dynamics of the tested sweet cherry cultivars when they were immersed in distillated water for 24 hours. It was found that the cracking ratio of very cracking susceptible sour cherry varieties had the same or higher cracking index than observed sweet cherries. It is in contrast with the general opinion (Chistensen, 1996) that sour cherries are less prone to rain induced fruit cracking than sweet cherries. We found differences between the cracking ration and cracking dynamic of the same cultivar in different years (2006 and 2013). It is in agreement Christensen’s (1996) opinion that the year effect cause big differences in the fruit cracking of cherries.
    European plums: We found differences in the cracking ratio and the cracking dynamics of the tested plum varieties when they were immersed in distillated water for 24 hours. A shorter term (6 hours) immersing in water caused three groups by their cracking susceptibility: „Very susceptible”: ’Révfülöpi’ and ’Szarvasi’; „Susceptible”: ’Besztercei’; „Less sensitive”: ’Bluefre’ and ’Cacanska rodna’. A longer term (24 hours) immersing in water resulted only two groups with significant differences: „Susceptible group”: ’Révfülöpi’, ’Szarvasi’ and ’Besztercei’; „Less sensitive”: ’Bluefre’ and ’Cacanska rodna’ Similarly the cherries we did not find correlation between the fruit size and cracking susceptibility of European plum cultivars. It was based on: the big fruit sized ‘Bluefre’ and middle sized ‘Cacanska rodna’ cracked in the lowest scale, during the small sized ’Révfülöpi’, ’Szarvasi’ and ’Besztercei’ cultivars cracked in higher scale We found positive correlations between the cracking susceptibility and total sugar content of tested plum cultivars. Cultivars with significantly lower sugar content (‘Bluefre’ and ‘C. rodna’) showed lower fruit cracking susceptibility than cultivars (’Révfülöpi’, ’Szarvasi’ and ’Besztercei’) with higher sugar content). We found close relationship between the relative (%) absorbed water amount and the fruit cracking susceptibility. Cultivars with higher absorbed water amount (’Szarvasi’-’Révfülöpi’-’Besztercei’) had higher cracking susceptibility.

  • Some biological properties of new sweet cherry cultivars in Bulgaria and their susceptibility to Blumeriella jaapii
    95-97.
    Views:
    230

    Investigations were made on 12 sweet cherry cultivars (‘13-S-22-8’, 'Sunburst', `Kozerska'., 'NY 13791', 'Royalton', 'NY 13688', 'Hartland', `Sumerset', 'Pollax', 'Patriotka Krima', 'Castor', and `Lapins') in an experimental orchard of cherry cultivar collection in the Institute of Agriculture at Kyustendil, Bulgaria during the period of 1997-2003. The trees were planted in 1996. All cultivars were grafted on Prunus mahaleb. Four biological properties of the cultivars were assessed such as blooming time, resistance to late spring frost, fruit ripening and fruit mass. Among cultivars, a good resistance to late spring frost was observed on cultivar 'Sunburst'. The fruit mass varied between 4.2 g (cv. 'Patriotka Krima') and 8.5 g (cv. `Sunburst'). The susceptibility of the cherry cultivars to cherry leaf spot caused by Blumeriella jaapii was assessed in mid-September in each year. The estimation of the rate of attack was made according to the grade of Townsend and Neuberger. All cultivars showed symptoms of cherry leaf spot but the degree of susceptibility was different. Cultivar `Patriotka Krima' was the least susceptible, while cultivar `Somerset' was the most susceptible to Blumeriella jaapii.

  • Susceptibility of some traditional pear cultivars of Hungarian and foreign origin to the pathogenic bacterium Erwinia amylovora
    41-45.
    Views:
    137

    Fire blight, a disease caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., has been causing serious damage in Hungarian pear plantations since 1996. A prospective control measure could be the use of resistant cultivars. For that purpose ten pear cultivars have been tested under laboratory and greenhouse conditions for resistance to Erwinia amylovora strains collected in Hungary. Six of these cultivars are Hungarian ones of unknown origin, while four are traditional old varieties. Resistant cultivars should serve as germplasm for future breeding. Inoculations were made with a mixture of different pear isolates of the bacteria collected from various growing regions of Hungary (Ea 21, 23), at a density of 5x108 cells/ml. Susceptibility/resistance has been assessed on the basis of intensity of blight symptoms observed on shoots, flower parts and fruits. Cultivars were assigned to three susceptibility groups (low, moderate and high). Complete resistance was not found among the cultivars tested. The highest level of resistance was found in cultivar 'Kieffer', while the other cultivars displayed either moderate or high susceptibility to infection.

  • Susceptibility of fruit of some plum and apricot cultivars to brown rot
    53-55.
    Views:
    252

    In this three-year study, incidence of brown rot (Monilinia spp.) on fruit of plum and apricot cultivars were evaluated in Kecskemét, Hungary. Results showed that most plum and apricot cultivars expressed symptoms caused by Monilinia spp, graded between 2 and 4 (10–75%) by the end of the summer in 2008–2010. Assessments on plum showed that only cultivars ‘Besztercei’, ‘Silvia’ and ‘Tuleu gras’ were partly tolerant to Monilinia spp., while the most susceptible cultivars were ‘Bluefre’ and ‘Stanley’. The most tolerant apricot cultivars were ‘Borsi-féle kései rózsa’, ‘Piroska’, ‘Pannónia’ and ‘Magyar kajszi’ while the most susceptible ones were cvs. ‘Budapest’ and ‘Mandulakajszi’. Susceptibility classes showed that only one plum (’Silvia’) and one apricot cultivar (‘Borsi-féle kései rózsa’) were available with low susceptibility.

  • Floral biological studies on pear cultivars in relation to fire blight susceptibility
    25-30.
    Views:
    149

    Floral biological characteristics that may influence cultivar susceptibility to fire blight were studied in 10 pear cultivars in two Hungarian orchards from 1999 to 2003. The receptaculo-ovarial, automorphic nectary is usually bigger in tolerant cultivars than in susceptible ones. Nectary stomata are meso- or xeromorphic. Susceptible cultivars tend to have more xeromorphic stomata, where guard cells are located 1-3 cell rows below the epidermis. The size of nectar chambers is usually smaller in susceptible cultivars. Floral nectar, consisting mainly of glucose and fructose, is more abundant and less concentrated if the cultivar is susceptible to fire blight. The amount of chlorogenic acid was higher in the flowers of tolerant cultivars than in susceptible ones.

  • Freeze Susceptibility of Fruit Buds in 67 Apple cultivars in Hungary
    29-35.
    Views:
    120

    Frost damage is one of the most important risks of apple production. Outstanding importance has been attributed to the frost resistance of flower-buds as decisive sites of fruit production. Browning of plants parts and tissues exposed to natural weather adversities are considered as effects of frost. In Hungary, frost damage on flower buds of both the market and new cultivars has not been assessed earlier. Observations referring to the consequences of frost damages of over four critical years, marked by their peculiar winter and spring frost hazards. Parallel observations have been made in four sites of the growing area in the Great-Plain region. 67 apple cultivars have been assessed. Each cultivar was represented by 3 trees, which were sampled at about 1-1.5 m height over ground, where the buds or inflorescences were picked for the purpose to assess the injury. The buds and flowers are cut longitudinally and rated visually according to the extent of browning of the organs and tissues. Susceptibility of different organs of the flower (pistils and anthers) were rated separately. According to our results, most resistant to spring frosts are the following cultivars: 'Gloster', 'Granny Smith' and appreciable tolerance is attributed in 'Gala' and 'Jonathan' with derivatives. Preliminary results that among the scab resistant cultivars, `Baujade', 'Rewena', 'Liberty', `Resi' and 'Renora' are rather frost resistant. Information, lacking hitherto, is obtained upon 'Reka' and 'Reglindis' as for their increased susceptibility.

  • Evaluation of fruit quality of old apple cultivars originating from the foot of the Carpathian Mountains, for utilization in breeding and in organic farming
    15-24.
    Views:
    291

    In the frame of the apple breeding program at the Department of Fruit Science old cultivars found in the Carpathian basin were involved in examination as well. Beside testing susceptibility to fire blight (Erwinia amylovora of old genotypes (historical, local and regional cultivars) originating from scattered orchards of Visk (foot of the Carpathian Mountains), fruit quality was also evaluated and other open-field observations were made.

    According to the results of inner content examinations, 'Szemes alma' and 'Sikulai alma', chosen as gene sources for breeding to resistance against fire blight, had inner content values worthy to mention in some aspects, and competing with those of the control cultivar 'Jonathan'. The quality of 'Pónyik alma', also recommended as a gene source is confirmed by the data of earlier literature. Further three cultivars ('Batul', 'Vilmos renet', 'Zöld sóvári') also proved to be good based on resistance against Erwinia amylovora, the first two cultivars are suitable from the point of view of fruit quality, too.

    In our field observations, susceptibility to apple scab and powdery mildew was evaluated. Among cultivars selected from the foot of the Carpathian Mountains on the base of resistance against Erwinia amylovora, the production value of 'Szemes alma' is worsened by its high susceptibility to apple scab. Further selected cultivars ('Sikulai', 'Pónyik alma', 'Batul', 'Vilmos renet') are not too susceptible to fungal diseases and their fruit quality is also suitable, therefore they can be recommended for direct planting in ecological farming or in restoring scattered orchards.

  • Incidence of two leaf fungal diseases in two plum training systems
    15-17.
    Views:
    414

    In a two-year study, we aimed to determine the susceptibility of four plum cultivars to two fungal pathogens of plum (Stigmina carpophila and Polystigma rubrum) in two training systems with tree spacings of 4 x 1.5m and 6 x 3m. Results showed that shothole symptoms were not detected on cvs ’Bluefre’ and ’Stanley’ in August, 2016. Disease incidence was above 50% in the case of ’Čačanska lepotica’ in both training systems in 2016. There were no significant difference between the two training systems. Shot hole incidence was lower in the 6 x 3m spacings compared to the 4 x 1.5m spacings on cv ’President’ in 2016. Cultivar ’Čačanska lepotica’ showed the highest incidence of Stigmina carpophila in the 4 x 1.5m spacing in 2017. Disease incidence of Stigmina carpophila was significantly lower in the 6 x 3m spacing compared to the 4 x 1.5m spacing. Shothole incidences on cv ’President’ were similar to the values in 2016 ranging from 40% to 60%. Leaf disease incidence was higher in the 4 x 1.5m spacing compared to the 6 x 3m plot. Low disease incidence (below 10%) was observed on cv ’Stanley’ in 2017 and only in the 4 x 1.5m spacing. There were no visible symptoms of blackhorn dotty in 2016 due to inadequate weather conditions for the Polystigma rubrum fungus. However, all the four cultivars were infected by Polystigma rubrum in 2017. The most susceptible cultivar was cv ’Čačanska lepotica’ with the highest disease incidence in the 4 x 1.5m spacing. Disease incidence of this cultivar was lower in the 6 x 3m spacing which was significantly less than in the 4 x 1.5m spacing. The least susceptible cultivar was ’Bluefre’ and symptoms were observed only in the spacing of 4 x 1.5m. The disease incidence of cv ’President’ was similarly low to cv ’Stanley’ in both spacings.

  • Blumeriella jaapii (Rehm) v. (Arx) infection of some sweet cherry cultivars in two years with different precipitation conditions
    37-39.
    Views:
    192

    We examined Blumeriella jaapii (Rehm) v. (Arx) infection on 21 sweet cherry cultivars in the cultivar-collection of the Experimental Station Pallag of the University of Debrecen, in 2004 and 2005. Considerable differences were detected in the infection degree of the different cultivars. In 2005, due to the more humid weather, the average infection highly exceeded data of the previous year. No symptomless cultivars were detected in either year. The least sensitive ones were Linda and the cultivar 11/106. The most sensitive cultivars were Early Müncheberg, Biggareau burlat and Round Solymári. Infection degrees of Alex, Rita and Vega were different from those of other cultivars on the basis of the two experimental years.

    It is important to consider both the specific weather conditions of the year and cultivar resistance at planning the plant protection system. It is recommended for each cultivar to perform a fungicide-spaying after the harvest.

  • Biochemical changes in pear (Pyrus communis L. depending on different phases of the dormancy
    47-50.
    Views:
    144

    Pear cultivars of variable frost tolerance were tested as for frost injuries suffered as a consequence of artificial freezing temperatures during the endodormancy as well as the ecodormancy. Damages were registered according to a visually defined scale, then peroxidase and polyphenol-oxidase activity was checked in buds, spurs and limbs. According to our results, 'Packham's Triumph' was the most frost tolerant cultivar. Regarding enzyme activity of both enzymes, the performance of cultivars displaying different susceptibility was also different in spurs as well as in buds. Results referring to the endodormancy were especially instructive. During the ecodormancy, data obtained at the same time indicated the differences existing between the developmental stages of dormancy in the respective cultivars.

  • Some structural characteristics of the flowers of apple cultivars with different susceptibilty to fire blight
    21-23.
    Views:
    112

    Several morphological characters of the hypanthium (size and form of the surface, the shape of the hypanthium) and anatomical traits (number and pattern of stomata) of apple cultivars (Malus domestica L.) with different susceptibility to fire blight were studied. The size of hypantium surface was calculated by modelling the hypanthium with a truncated cone. Three types of hypanthium surface form have been revealed: straight, convex and a complex "shouldered" one. The angle between the style and the wall of the hypanthium was narrow or wide. The stomata on the hypanthium surface can be arranged in a zone in the middle third of the hypanthium or dispersed more or less evenly. The number of stomata/flower substantially differed among the cultivars examined. The highest stomata number was detected in the flowers of the tolerant cultivar (Freedom)

    No single characteristics of the hypanthium could convincingly be correlated with susceptibility to fire blight. We suggest, however, that combination of morphological properties that sustain moist environment in the hypanthium contribute to susceptibility.

  • Some biological features of cherry leaf spot (Blumeriella jaapii) with special reference to cultivar susceptibility
    91-93.
    Views:
    526

    In this review, some important features of biology are summarised for cherry leaf spot (Blumeriella jaapii). In the first part of the review, the geographical distribution of the pathogen and the causal organism are described. Disease symptoms and disease cycle of cherry leaf spot are also shown. Special attention is given to hosts and then several cherry cultivars.are described in relation to their susceptibility to cherry leaf spot.

  • Sunburn incidence of apples is affected by rootstocks and fruit position within the canopy but not by fruit position on the cluster
    45-51.
    Views:
    220

    Authors investigated sunburn incidence of apples on the combinations of three different growth inducing rootstocks (M.9,MM.106 and seedling) and five varieties (‘Smoothee’, ‘Golden Reinders’, ‘Granny Smith’, ‘Gloster’ and ‘Jonagold Jonica’). Symptoms were classified as sunburn browning, sunburn necrosis and photooxidative sunburn. The frequency of symptoms was recorded at various parts of the canopy (N, E,W, S, and lower canopy, upper canopy) and on the cluster (terminal, lateral). Cultivar susceptibility varied between 0.30 and 5.65% on M.9 rootstock, ‘Granny Smith’ seemed to be the most susceptible cultivar whereas relatively low percentage of damaged fruit was observed for ‘Gloster’. On MM.106 and seedling rootstocks, damage level was significantly lower than on M.9. Remarkable differences were not observed in the share of the three sunburn types between cultivars. The most common symptom observed was sunburn browning. Far less fruit was affected by sunburn necrosis and photooxidative sunburn. Photooxidative sunburn symptoms were not found on ‘Granny Smith’ and ‘Gloster’ fruits on MM.106 rootstock. Latter cultivar did not show sunburn necrosis symptoms either. With increasing growing vigor of the rootstocks the share of sunburn browning increased. Fruits with sunburn symptoms were found in a great majority on theW quadrant of the trees. This was true for all cultivars. Remarkable differences in the location within the canopy of affected fruits between the three types of sunburn were not observed. Specific distribution of sunburned fruit was observed along the vertical axis of the canopy, too. Most of the damaged fruit were found in the upper canopy. This is particularly true for trees on vigorous stocks such as MM.106 and seedling. On M.9 rootstock, depending on cultivars 5.9 to 38.9% of sunburned fruit was located in the lower canopy. Most common symptom in the lower canopy was the sunburn browning, however symptoms of sunburn necrosis were not found at lower canopy level. Low rate of photooxidative sunburn was observed such lower canopy conditions. Sunburn incidence was very similar on king or side fruit. Significant differences were not found in the share of each sunburn types between fruit positions on the cluster. This was not influenced by rootstocks either.

  • Observing population changes of thrips (Thysanoptera) species damaging forced pepper and their natural enemies
    55-60.
    Views:
    188

    By the strengthening of environmental protection and food safety efforts in Hungary, integrated and especially biological pest control methods should increasingly put forward, for which a solid knowledge on the life course and efficiency of natural enemies applied against certain pests is necessary. Pepper has distinguished significance in domestic vegetable forcing, and the profitability of production is determined primarily by the efficiency of the control of thrips pests. This is why we attached great importance to study what results may be expected by introducing arthropod predators (Amblyseius cucumeris, Orius laevigatus) to control thrips species under domestic conditions on rock wool in a long vegetation period pepper culture. We also liked to find out what kind of role the cultivars play in the change of phytophagous and zoophagous populations. The A. cucumeris predatory mite introduced in late January proved to be effective in controlling thrips pests until mid-April. Despite repeated introductions, the predatory bug O. laevigatus (Heteroptera: Anthocoridae) did not proliferate. Among the three pepper cultivars (Hó, Keceli, Titán) grown at Ráckeve, thrips species proliferated in the highest number on cultivar 'Hó', while the population of predatory mites was lowest on the cultivar 'Titan', compared to the other two cultivars.

  • Fire blight (Erwinia amylovora) susceptibility of old Hungarian apple cultivars
    35-38.
    Views:
    139

    The aim of the Hungarian apple breeding program started in the Department of Fruit Science was to find resistant apple cultivars against major diseases (scab, powdery mildew, fire blight). The outbreak of fire blight (Erwinia amylovora) in 1996 motivated us to search new resistant sources principally from old traditional apple cultivars. First of all, cultivars have been gathered since 1997 from Carpathia (Visk) and evaluated between 2001 and 2003. In this recent study evaluation of resistance of old Hungarian genotypes to fire blight collected from the English National Fruit Collection (Brogdale, Faversham) is presented.

    13 old Hungarian apple cultivars in 2002, and 38 genotypes in 2005 have been evaluated. We used `Idared' and 'Jonathan M41' as susceptible controls and 'Liberty' and 'Remo' as resistant ones. Shoots of two-year-old potted plants were inoculated with a mixture of virulent E. amylovora isolates (Ea2, Ea60, Ea67) at a concentration of 5 x 108 cells/ml. Resistance of apple cultivars was evaluated weekly, four times after inoculation by disease severity of symptoms. Numbers of bacterial colonies in 1 cm length shoot were determined in the fourth week after infection.

    8 cultivars in 2002 and 9 cultivars in 2005 displayed notable resistance to fire blight based on one-year data. Based on the coincident data of both years, out of the cultivars collected also from Carpathia ‘Pónyik', and `Sikulai' were found to be resistant and gene sources additional old Hungarian valuable apple genotypes could be selected: `Szabadkai szercsika' and `Tordai piros !davit'. The cultivar `Szemes alma' originated from Visk has proved to be recurrently resistant.

    The number of bacterial cells in shoots of the investigated cultivars correlated with the severity of symptoms. With this method, which was introduced by us earlier, we can screen cultivars displaying weak visible symptoms, which cannot be proposed as a source of resistance because of their latent infection.

  • Effect of Erwinia amylovora infection on peroxidase enzyme activity in resistant apple cultivars
    37-39.
    Views:
    140

    Two apple cultivars that display enhanced resistance to fire blight (causal agent: Erwinia amylovora) were selected. The aim of the present study was to characterize the peroxidase (POD) enzyme activity of `Szemes alma' (a historical cultivar) and MR-03, (a Hungarian multiresistant hybrid of 'Prima') and compare them to susceptible 'Jonathan M 40' and resistant 'Remo' controls. Peroxides enzyme activity during E. amylovora infections was investigated in artificially infected apple shoots. Increases in enzyme activities were observed in a `Jonathan M40' and in 'Remo', MR-03, `Szemes alma' cultivars. There was a consistent relationship between total enzyme activity and fire blight disease severity. High activity of the peroxidase was positively correlated with the degree of resistance to fire blight. A general hypothesis that POD activity is related to fire blight susceptibility/resistance is supported by our results.

  • Possibilities of brown rot management in organic stone fruit production in Hungary
    87-91.
    Views:
    282

    In this study, possibilities of environmentally-friendly plant protection against two brown rot species was summarized for organic stone fruit orchards. Symtomps of the two most important brown rot species (Monilinia fructigena (Aderh. & Ruhl.) Honey and Monilinia laxa (Aderh. & Ruhl.) Honey) were described and then cultivar susceptibility to brown rot was discussed. Several sustainable plant protection methods were selected and discussed in details such as mechanical, agrotehcnical, biological, and other control possibilities (elemental sulphur, lime sulphur and copper).

  • Comparative anatomical study of leaf tissues of scab resistant and susceptible apple cultivars
    43-45.
    Views:
    178

    According to previous studies some anatomical features seem to be connected with resistance or susceptibility to scab caused by Venturia ineaqulis (Cke./Wint.) in case of a given cultivar. Study of leaf anatomy of three scab resistant (‘Prima’, ‘Florina’, MR–12) and two susceptible (‘Watson Jonathan’, ‘Golden Delicious Reinders’) apple cultivars have been made. Preserved preparations made of leaves has been studied by light microscope. Studied parameters were: thickness of leaf blade, thickness of palisade and spongy parenchyma, thickness of epidermal cells, thickness of the cuticle. By measuring leaf thickness and epidermal cell thickness visible differences appeared in certain cultivars, while most conspicuous difference has been shown in thickness of the cuticle.

  • Possibilities of blossom and twig blight management in organic stone fruit production
    103-105.
    Views:
    197

    In this study, possibilities of environmentally-benign plant protection against blossom and twig blight were summarized for organic stone fruit orchards. Symtomps of Monilinia laxa (Aderh. & Ruhl.) Honey) were described and then cultivar susceptibility to blossom and twig blight was discussed. Several sustainable plant protection methods were selected and discussed in details such as mechanical, agrotechnical, biological, and other non-chemical control possibilities (stone powders, plant extracts and restricted chemical materials).