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The effect of tree growth of sweet cherry cultivars ‘Burlat’, ‘Kasandra’, ‘Justyna’, ‘Early Korvik’, ‘Kordia’ a ‘Tamara’ on rootstocks Weigi series (Weigi® 1, Weigi® 2 and Weigi® 3) was evaluated in the experimental orchard in location Holovousy (district Jičín, Czech Republic) in years 2019–2023. The diameters of the trunk below the branching of the crown at a height of 60 cm above the grafting site were measured. Tree growth was evaluated according to trunk diameter increase after five years of growing converted to trunk cross-sectional area (TCSA) expressed in cm2. As standard roostock was used Gisela 5 that is the most used rootstock for sweet cherries in central Europe. The highest tree growth was in the experimental planting recorded for cultivars ‘Burlat’ and ‘Kasandra’ on Weigi® 3 rootstock with 38 cm2, respective 34.2 cm2 increase of TCSA. The lowest tree growth was recorded for cultivar ‘Justyna’ on Gisela 5 and Weigi® 2 with 15.2 cm2, respective 16.2 cm2 TCSA increase and for cultivar ‘Tamara’ on Gisela 5 with 19.3 cm2 TCSA increase.

The effect of mycorrhizal fungi on the rooting and growth of apple trees was evaluated in experimental plantings in Research and Breeding Institute of Pomology Holovousy Ltd. at location Holovousy, district Jičín, Czech Republic. Product Symbivit that contains five species of mycorrhizal fungi was applied during planting on apple cultivars ‘Angoldʼ, ʻAntopaʼ, ʻIdapazʼ, ʻMeteorʼ and ʻTopazʼ on M9 rootstocks. Trees were planted in the spring 2022. The planting was without drip irrigation. Mycorrhizal fungi were applied during planting directly to the roots. Differences in the diameter of tree stems in the experimental variants were compared with control variants. Measurements were done after planting, in fall 2022 and 2023. In the first year of cultivation, a significant difference in growth was noted in trees treated with the product compared to control. The diameter of tree trunk with the application of mycorrhiza was 1.8 mm while in the control without application 1.4 mm in the first year, respective 4.5 mm and 4.1 mm after the second year of cultivation.

Forecasting models for predicting the development of diseases and pests are based on the measurement of meteorological data such as temperature, precipitation, duration of leaf wetness etc. Predictions of the development of individual developmental stages of pests and suitable conditions for pathogen infections are then modelled from these values. Cultivation systems for growing apple trees have changed significantly in recent years. New plantings are in a high density, apple plantings are covered with anti-hail nets. All these changes have an effect on the microclimate of the plantings and thus also on the development of pests and pathogens. In majority, the air temperature measured at the nearest meteorological station at a height of 2 m above the surface enters in models as a variable. However, it cannot be assumed that even modelled insect pests occur exactly at this height. The aim of this study was to assess how the detected temperature differences and their daily course in individual planting height levels will be reflected in the resulting values of temperature sums, which are most often used for modelling the development of insect pests in orchards. It was found, that for hourly average temperatures above the 5 °C threshold, the differences ranged within ± one day for almost the entire growing season from April to early September. At a height of 3 m, the temperature totals were slightly higher throughout. The specific amount was therefore reached approximately one day earlier, while at 0.5 m it was lower, so this value was reached less than a day later. For other models based on sums of daily degrees +5 °C or sums of daily and hourly degrees +10 °C, the differences were 2–3 days.