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Flower visiting activity of honeybees on fruit species blooming subsequently
12-16.Views:1107In the small demonstration orchard of the College Faculty of Horticulture at Kecskemét the blooming time, the flower density and the honeybee activity was observed at a number of cultivars of 20 flower species during four consecutive years.
Fruit crop species were in flower during 3-4 months altogether. The blooming period of them was classified into five groups as early (almond, apricot, gooseberry), middle early (sweet cherry, red currant, currant-gooseberry, black currant, white currant, peach, plum, sour cherry), middle late (pear, strawberry, apple), late (black elder, quince, medlar, raspberry, blackberry-raspberry) and very late blooming period (blackberry). The blooming period of the members of the groups of early and medium early blooming often coincided partly and the same happened between the medium and the medium late as well as between fruits of late and very late flowering.
The flower density of some fruit species is extremely variable (currant-gooseberry, medlar), while at others it is fairly stable and evenly dense in consecutive years (sour cherry, sweet cherry, strawberry). At other fruit species it is moderately changeable. Some fruit species tended to attract more honeybees than others (plum, apple, quince, medlar) and some of them tended to attract much less (black elder, pear) but most species can be regarded as of medium attractivity.
On the flowers of some fruit species (pear, strawberry, quince) honeybees gathered pollen predominantly. At most fruit species however pollen and nectar gathering behaviour seemed to be gradually changing during the season. Namely most honeybees tended to gather pollen at the flowers of the early blooming fruit species, but on the other hand typical foraging behaviour gradually shifted to nectar gathering at the flowers of fruit species of moderate and late blooming periods.
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Structural differences arise between fruit cuticles of two apple cultivars during long term cold storage
26-29Views:584Apple fruits are covered by hydrophobic cuticle that provides protection against desiccation, pathogens, excessive water absorption and radiation. The features of cuticle affect the quality and storability of the fruits. It was aimed to evaluate the correlation between peel ultrastructure and weight loss in fruits covered by waxy bloom (cv. Florina) and without bloom (cv. Red Rome van Well) during 4-month cold storage. SEM (scanning electron microscopy) was used for visualization of the fruit surface and fruit weight was also measured. Several studies have revealed that there may be correlation between the ultrastructure of cuticle and its water permeability. Our results confirmed this phenomenon in case of two cultivars. The weight loss per fruit surface area unit of ‘Florina’ was found significantly higher than that of ‘Red Rome van Well’. At the same time the cuticular surface of the fruits contained more micro-cracks in case of the former cultivar. These data confirmed the relationship between the density of cuticular micro-cracks and the water vapour permeability. We concluded that this feature is more significant than the amount of natural waxy bloom on fruit surface.
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Effect of Erwinia amylovora infection on peroxidase enzyme activity in resistant apple cultivars
37-39.Views:436Two 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.
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Comparative performance of traps for the Mediterranean fruit fly Ceratitis capitata Wiedemann (Diptera: Tephritidae) baited with female-targeted or male-targeted lures
11-14.Views:437Results of trapping trials in Italy confirmed that the non-sticky CSALOMON® VARs+ funnel trap was highly efficient for the capture of Mediterranean fruit fly (Ceratitis capitata Wiedemann) (Diptera: Tephritidae), when baited with either male-targeted (trimedlure), or synthetic female-targeted (ammonium carbonate, ammonium acetate, trimethylamine, putrescine) baits. Trimedlure-baited traps caught ten times more flies (all males), than traps with synthetic female-targeted lures (which cauught predominantly females). Although less efficient, traps with the female-targeted lures had the significant advantage over trimedlure that they attracted predominantly females, so in cases when for control or experimental purposes the capture of female flies is more informative (i.e. timing of egg-laying, fertility and fecundity studies, etc.), these lures would be the best choice. The present results suggested that putrescine could be left out from female-targeted lure combinations without dramatic change in activity.
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Scab resistance in Malus sp. progenies - inheritance and resistance stability
9-15.Views:260Susceptibility of progenies of some Ma/us species to apple scab was evaluated. Susceptibility of hybrid families was observed first in greenhouse after artificial inoculations by the suspension of the pathogen, Venturia inaequalis (Cooke) Wint., then in open field. The Hungarian type of Malus floribunda, which proved to be scab resistant in our examinations, has a positive effect on the segregation of progenies to resistant and susceptible individuals as a male parent, not depending on the rate of susceptibility of the other parent. However, the German type of Malus floribunda and Malus prunifolia act as dominant, highly susceptible parents.
Malus x purpurea and Malus baccata, which proved to be highly susceptible to apple scab in open field and in artificial inoculations, transmits its susceptibility only slightly to its progenies as a male parent.
According to our experiments, the inheritance of scab resistance of Malus floribunda cannot be considered as monogenic, as published by other authors.
Scab susceptibility of parents influences the segregation of progenies to resistant or susceptible individuals. The moderately scab susceptible `Idared' as female parent has a statistically proved positive effect on the segregation of its progenies.
More factors indicate the appearance of a new race of Venturia inaequalis (Cke.) Wint.: change of the symptoms in the greenhouse; considerable increase of susceptible individuals after greenhouse inoculation in 1997; more and more progenies of the male parent Malus floribunda became susceptible to scab in open field.
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Chemical communication with volatile semiochemicals in Phyllotreta species (Coleoptera, Chrysomelidae): a minireview
93-100.Views:555Phyllotreta species (Coleoptera, Chrysomelidae, Halticinae) rank among the most important horticultural pests in the Northern Hemisphere. Leaf damage caused by flea beetles upsets the water balance, blocks plant growth and sometimes causes a high level of mortality of seedlings. Several species are known to act as vectors of numerous pathogens as well. Chemical communication plays an important role in the host finding, feeding and oviposition behaviour of flea beetles. In the first phase volatile mustard oils (isothiocyanates and thiocyanates) are released from the host plants through the decomposition of non-volatile glucosinolates (chemicals specific to Cruciferae) by myrosinase, and beetles are attracted to the source of release from a distance. Among the isothiocyanates, allyl isothiocyanate is the longest known and widespread compound utilized in the host-plant location of Phyllotreta species, but some species may have a stronger preference to other isothiocyanates or thiocyanates. The attractive effect of the plant volatiles is enhanced by the emission of a male-produced aggregation pheromone. The presence of such a pheromone was first demonstrated in Phyllotreta cruciferae Goeze. In this species R5R,5aS)-1,1,5,8-tetramethy1-1,2,3,4,5,6,5a-heptahydrobenzo[1,2-a][7]annulene] was found to be the main pheromone component. Significant attraction by the pheromone was recorded only in the presence of ALLYL ITCN. The biological activity of the pheromone compound was connected to the plus (+) chirality. The same component seems to be occurring also in the pheromones of several other Phyllotreta spp. as well, suggesting a wider occurence in the genus. Once attracted by the joint effect of plant volatiles and aggregation pheromone, the presence of the non-volatile glucosinolates in the plant tissues is necessary for continuous feeding. Aggregations of flea beetles on suitable host plants, which result from the joint effects of plant-derived and pheromonal chemical cues detailed above may also be good rendez-vous occasions, increasing the probability of encounters with the opposite sex and mating in the vicinity of the optimal oviposition site. Due to the horticultural importance of Phyllotreta spp., deciphering details of their chemical communication has considerable significance in the development of new methods of integrated control.
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Preliminary data on attractiveness of phenylacetaldehyde-based lures on economically important plant bug pests (Hemiptera: Miridae)
87-94Views:740Several plant bug species (Miridae) are important pests of crops and vegetables, thus monitoring them is of essential importance for effective pest control. During the current, preliminary study synthetic plant volatile combinations were tested in field conditions in Hungary in alfalfa fields. Beside semiochemical baited traps, sweep-netting was also performed. In the experiments three plant bug species were found in higher numbers: Adelphocoris lineolatus, Lygus rugulipennis and L. pratensis. As a novel, interesting finding L. pratensis was attracted to phenylacetaldehyde baited traps. For all species, both males and females were trapped in all combinations. Sweep-netting and semiochemical baited traps showed different efficacy in case of the three species, as sweep-netting catches were highly biased for A. lineolatus, which indicates the higher efficacy of this method as compared to the tested semiochemical-baited traps. On the other hand, semiochemical baited showed better performance for L. rugulipennis and L. pratensis. For these species none of the tested combinations performed better than phenylacetaldehyde baited traps. The potential implication of results in view of monitoring are discussed.
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Effect of N, P, K and Mg fertilizers on some vegetative and generative parameters of a sweet cherry cultivar
27-30.Views:930This two-year-study was aimed to provide results on the effect of nitrogen, phosphorus, potassium and magnesium fertilizer treatments (control, NP, NPK, NPKMg) on vegetative and generative features of the sweet cherry cultivar ‘Carmen’. Examinations were performed in an orchard planted in 2012 on Prunus mahaleb rootstock with spacing of 5 x 2.5 m. All treatments improved the vegetative features of the sweet cherry trees in both years of 2016 and 2017. Fertilizer treated trees increased trunk cross section area (TCSA) with 51.3-63.1%, while control trees showed 48.3% trunk growth increase. Yields of control trees were lower in both years (5.9-7.2 kg/tree), than that of the fertilized trees (7.8-11.3 kg/tree). Treatments also increased the phosphorus (16-22%), magnesium (12-20%) and potassium content (3.5-18%) of the fruits compared to control treatments.
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Rheological evaluation of industrial tomato in raw and processed condition
60-64.Views:447Tomato (Lycopersicon esculentum Mill.) is the second most important vegetable with one of the biggest producing areas worldwide, and an increasing tendency in Hungary as well. To fulfil the growing demands of the industry the producers must use the most suitable genotypes for the given conditions. In the experiment six genotypes (‘Heinz 1015 F1‘,‘Heinz 9478 F1‘,‘Kecskeméti 407‘,‘NUN254 F1‘,‘Prestomech F1‘ and ‘Rustico F1‘) were evaluated for different quality parameters: fruit shape index (length/diameter), firmness (g cm-2), force needed to tear the skin (kg-1) and consistency of tomato puree (g*sec). According to the results, the ‘Heinz 1015 F1‘ and ‘Heinz 9478 F1‘ were the most suitable genotypes for industrial processing in the mean of fruit quality. Strong positive correlation between consistency of juice and fruit shape index (r=0.891) and firmness of berry (r=0.882) was confirmed. The results have proved the necessity of these quality parameter measurements, which are important for the evaluation of raw material.
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Evaluation of cauliflower genotypes by different growing method
11-14.Views:484Cauliflower is currently cultivated on 350-400 thousand hectares in the world and around 1500 ha in Hungary. Its cultivation requires considerable expertise as it is sensitive to environmental factors and adequate nutrient supply. The aim of our experiment was to compare three genotypes (Abeni, SV5777 AC and Telergy F1) by different growing method – under plastic tunnel and on open field. On open field the planting was on 19th of March, 2018, the row and plant distances were 45 and 35 cm. Under plastic tunnel the transplants were set out on the same day with the same genotypes as on open field, with 55x45 cm arrangement. The results have proved that cauliflower curds from plastic tunnel was two times bigger than on open field. The more protected environment had a positive effect not only on the mass of the curd, but also on the biomass production. Among the examined genotypes Abeni showed the highest yield (about 1 kg/plant) under plastic tunnel. The shape of the head is important for the market. According to our data, we measured the width and height of the curd. Open field conditions induced wider curd with longer stem and caused lower product quality and weaker correlation between the parameters than plastic tunnel.
