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  • Study on the emergence of the raspberry cane midge (Resseliella theobaldi Barnes) on the basis of temperature data and catches of sex pheromone traps
    23-26.
    Views:
    164

    Effective chemical protection against the raspberry cane midge (Resseliella theobaldi) should be based on the monitoring of the emergence of the pest. Before the application of sex pheromone traps, the results of several international studies carried out to determine the accumulated temperature needed by the larvae to become adults showed differences in the calculated data. The aim of this paper was to give information on the time of cane midge emergence by using sex pheromone traps and different methods of accumulated temperature calculations. On the basis of three years' results, the use of accumulated soil temperatures turned out to be reliable for the prediction of cane midge flight, and the relative standard deviation was the smallest in the case of 0 °C compared with other values applied as supposed biological zero points. According to our studies, 665 day °C are required for the development of one generation of the raspberry cane midge during the vegetation period. The emergence of the first generation was found at 451 day °C.

  • Study on the time of emergence of the first generation of raspberry cane midge (Resseliella theobaldi BARNES)
    43-45.
    Views:
    172

    The raspberry cane midge (Resseliella rheohaldi BARNES) is a major pest of raspberry in Europe. The accurate prediction of adult midge emergence is an important part of integrated raspberry protection. Calculation of the accumulated effective temperature may be used in prediction. The values of the critical accumulated effective temperature needed for the first flight of the midge differ in the European regions. In our experiments we investigated the first generation of the midge in Hungary. Our results show that the critical accumulated effective temperature for the first flight was the lowest compared with results received in other European countries. The emergence of males of the first generation was found at 145-194 day °C, and females started laying eggs a few days later.

  • The application of A HEAT SUM MODEL for the budburst of sour cherry varieties grown at Újfehértó
    105-112.
    Views:
    258

    Experiences of the last decades showed univocally that the climatic changes, especially the warming up, influenced clearly the phenology, i.e. speed of growth and development of plants. To check the effects, the phenological studies became a topic of special interest. Our research has been performed at Újfehértó, the Research Institute of Fruit Growing and Extension, where the respective database accumulated observations during the period 1984–2005, where the meteorological data as well as the parallel phenological diary referring to the varieties ’Újfehértói fürtös’, ’Kántorjánosi’ and ’Debreceni bôtermô’ during the period 1984–1991 have been utilised. The method of calculating the sum of daily mean temperatures, “degree days”, is based on the observation that the plants are able to utilise cumulatively – in growth and development – the temperature above a set basic temperature. Our phenology model examined the correlation between the sum of degree days and the date of sprouting (budburst). The basic temperature has been determined by optimization, above which (threshold temperature) the accumulation of daily means was most active, or alternatively, below which the daily means are most sensitively expressed in the phenology. The model has been extended to the calculation of the end of rest period (endodormancy) – by optimization as well. Our phenology model will be suitable for two main purposes: for estimating the time of budburst for the Hungarian region during the next decades calculated on the basis of regionally downscaled climate models; on the other hand, by applying our model, the risk of damage caused by spring frosts could be estimated more exactly than earlier.

  • Damages caused by winter frosts, their temporal variation and frequencies in the main fruit growing region of Transdanubia and of the East Tisza regions of Hungary
    89-97.
    Views:
    197

    The aim of the study was the study of winter frost damages, especially their changes expressed in temporal frequencies on the main fruit growing regions of the country. In our earlier paper, we introduced the calculation with the term LT50 as the quantitative expression of temperature threshold, when the lethality halves the survival of plant organs, buds or cells causing 50% death rate. The damage is highly dependent on the temperature and on its duration (length of time), but not at least on the frost tolerance of the fruit trees. The incidence and severity of damage is analysed according to the apricot and peach varieties of their different susceptibility or tolerance too. Four fruit growing regions, two of the in Transdanubia and two belonging to the regions east of the Tisza river have been selected to trace the incidence and severity of frost damages. For that purpose, we analysed the history of the past 60 year period, 1951–2010, utilising the database of the network of 16 meteorological stations of the countrywide service. Being aware of the values of LT50 during the rest period and afterward, the compulsory dormancy caused by low temperature, the number of days, the probability of frost damage could be predicted. The role of the orographical profi le, the height above sea level and the exposition of plantations are also decisive. Within the same plantation, 20–30 m difference of level may cause large diversity in temperature and frost damage. Air circulation and regular incidence of winds within the Carpathian basin modify the occurrence and severity of damages. Lowlands near the southern and northern country borders are particularly exposed to winter frosts. Most damages are reported in February, as temperatures below –20 °C especially if the fi rst part of the winter was mild, or in January was a warm period. With the end of the physiological rest period of the trees, the frost-susceptibility increases signifi cantly, and a cold period of –15 °C may cause heavy damage. This study proves that tolerance of varieties infl uence the damages substantially. By planting frost tolerant varieties, winter frost damages could be diminished by 40–50% at the same growing sites. Present results may also offer a tool to estimate the risk of frost damages and express the security of yields at a given site based on the data accumulated in the database over many years.

  • Impact of planting dates on yield and pod quality traits of snap bean under short-temperate season climates
    57-63.
    Views:
    132

    Snap bean, a warm-season crop, have low frost tolerance. The optimal temperature for seed emergence and plant growth is important. Therefore, appropriate planting dates for adapted varieties has paramount significance in improving pod yield and quality of snap bean under short cool season climates. Three snap bean cultivars planted at 3 different dates were examined to evaluate the effects of planting dates on snap bean pod yield and quality traits in a 2-year study in a short season climate in Manitoba, Canada. Results of this study showed that three, two weeks apart, planting dates had a non- significant effect on marketing yield of three different cultivars tested in this study. Planting dates showed significant effect on un-marketable yield, pod fresh weight, pod length and total soluble solids. Higher marketable and un-marketable yields along with longer pod length and soluble solids, in all three cultivars, were more profound when seeded at mid and late planting dates. Snap bean grew under higher temperature and accumulated more growing degree days (GDD) when planted in mid June and early July when compared to early June planting. These results conclude that marketable yields of snap bean were not significantly affected by planting dates when seeded-two weeks apart-in shorter growing environments which allow commercial and market gardeners, in northern areas with shorter growing seasons to optimise planting snap bean, without reducing pod yield and quality.