László Kocsis

The present study investigated whether different grafting combinations (hypobiont-epibiont) of Vitis spp. influence root infection with phylloxera and thus vine biomass on potted 2-year-old plants. The study was conducted simultaneously at two locations in Slovenia (VEM) and Hungary (GF). The dormant canes of ‘Johanniter’ (JOH), ‘Riesling’ (RR) and Vitis berlandieri × Vitis riparia ‘Teleki 5C’ (5C) were hetero-grafted (each with each) and autografted (each with itself), so that nine plant combinations were used for the trial. The roots of the experimental plants at different ages (1–2 years) were infested with two phylloxera populations originating from two locations (VEM, GF). Plant growth was quantified 120 days after inoculation by measuring root and shoot biomass, while the extent of phylloxera infestation was assessed by the number of feeding sites (nodosities, tuberosities) and the number of larval stages of phylloxera. In most cases, the genotype of the hypobiont influenced the degree of phylloxera infestation on all roots of the two-year-old root system. At both locations, the highest number of nodosities and the highest increase in phylloxera population was observed on the autografted Teleki 5C (5C/5C). The phylloxera biotype derived from Vitis vinifera roots (GF) induced tuberosities, especially on roots of combinations where JOH and RR were used as hypobionts. No correlation was found between biomass and phylloxera infestation. The hypobiont genotype had no effect on cane biomass at the end of the growth cycle at either experimental site.

Vineyard floor management has been widely discussed for many decades, but it is still unclear how its intensity levels change the fungal community structure of grape rhizosphere. Our objective was to examine the density and rate of the habitats of fungi in three vineyards that differ only in the methods of tillage procedure applied, namely intensive, extensive and none (abandoned). The hypothesis was that in the cases of lower intensity or no soil tillage, there would be a higher level of fungal diversity with a lower ratio of pathogen strains in grape rhizosphere. In the course of this research, it has been determined that the level of fungal colonization of roots is the highest in the extensively managed vineyard, unrelated to season (spring and summer). Four of the five fungal genera detectable in all of the three sampled vineyards are registered as opportunist grape pathogens, however the fifth one, Trichoderma, is commonly used in biological plant protection. The diversity of fungal communities in grape rhizosphere, in accordance with the expectations, was the lowest in the intensively cultivated and highest in the abandoned vineyard, and it was not affected by seasons. The proportion of opportunist plant pathogen groups was higher in the intensive variant than in the other two (less-intensive variants); therefore, it is possible to conclude that soil under similar conditions but disturbed by intensive tillage methods tends to exhibit lower suppressivity.