Pomegranate (Punica granatum L.), the hystoric fruit and ornamental crop native to Iran and North India is widely planted in the Mediterranean and became popular in the house gardens of northest parts of Europe (Fernandez et al. 2014) including Hungary. In August 2020 necrotic black lesions and serious defoliation were observed on 60% of 1-3 year old pomegranate trees (cv. Wonderful) in a horticultural nursery near Gödöllő, Hungary (47°36'00.9"N 19°21'26.5"E). Symptoms started as small irregular dark brown spots on the leaves, which later increased in size (2.6 ± 0.9 mm). Ultimately, the entire leaf turned yellow, defoliation resulted in damage on (6) - 8 - (15)% of the leaves. Then, black pycnidia with unicelled, elliptical to fusiform, colourless conidia (Avg. 50 conidia: 2.4 - (3.6) - 3.9 × 10.2 - (13,1) - 17.9 µm) developed on the surface. These morphological features matched those described earlier by Van Niekerk et al. (2004) and Alvarez et al. (2016) for C. granati. Conidia from pycnidia were directly transferred to potato dextrose agar (PDA) by sterile needle. The plates were incubated at 24°C in the dark. Light yellow colonies with whitish aerial mycelia and later black globose pycnidia were observed. Mass of conidia oozed from pycnidia after 15 days of incubation. Pathogenicity tests were carried out on 1-year-old potted P. granatum trees (cv. Wonderful) with 5 replicates in the greenhouse. Ten, randomly selected leaves were inoculated per plant. 7-mm mycelial plugs from the edge of 10-day-old colonies were placed directly on disinfested (2% NaOCl solution, than sterile distilled water) leaves. The plants were covered with plastic film for 3 days after inoculation (26±3°C and 87±3% relative humidity). Pathogenicity was also tested on nonwounded, surface-disinfested fruits by mycelial plugs in 3 × 3 replicates. Inoculated fruits were placed in large grass vessels for 15 days (24±2°C and 80±5% relative humidity). Uncolonized, sterile PDA plugs were used as controls in both cases. Dark brown legions developed after 9-12 days on the plants in the greenhouse. On pomegranate fruits, the fungus colonized the fruit after 7-8 days, followed by fruit rot. In some cases, after 2 weeks pycnidia developed on the skin surface. No decay were present on control leaves or fruits. The pathogen was reisolated from all infected tissues and identified as C. granati, thus fulfilling Koch's postulates. For molecular identification, total genomic DNA of the isolate was extracted from the growing margins of colonies on PDA and partial sequence of internal transcribed spacer (ITS) and translation elongation factor 1-alpha (tef1) were amplified by PCR using primers described by Alvarez et al. (2016). Sequence data of the Hungarian isolate of the ITS region (GenBank acc. no. MW581953) showed 99.8% identity (559 bp out of 560 bp) with C. granati sequences deposited in GeneBank (Acc. nos. MH860368, MH855389 and KX833582). Considering tef1 sequence of the Hungarian isolate (OM908764) obtained had complete identity with other published C. granati isolates (KX833676, KX833682). C. granati has been previously reported on pomegranate from Europe (Palou et al. 2010, Pollastro et al. 2016). Based on morphological and molecular studies, this is the first record of C. granati in Hungary. The economic importance of this disease in currently limited in Hungary due to pomegranate is rather an ornamental crop, however, the first cultivation trials have been already started. There is a risk that the spread of the pathogen began with the infected propagating material, as a result the disease may outbreak anywhere in the country.

Globalisation, climatic changes, and increasing consumer demand have forced the intensification of agricultural production. Thus, vineyards have crossed the boundaries of the original production zones and extended towards suboptimal areas, increasing the potential risk of damaging disease outbreaks. Therefore, there is a rising need for a complex and empirical revision of the interfering effects between grape infection and other external, large-scale factors such as environmental conditions and management practices. Although external abiotic and biotic factors could determine the infection levels of grape disease in a complex way, existing studies focus on the short-term effects of only a single or very few potential factors. In this large-scale study, we aimed to reveal the long-term impact of specific factors regarding vineyard characteristics, applied crop management and grape variety features, which could determine the infection severity of primary grape diseases (grey mould, downy mildew and powdery mildew) using a citizen science approach in Hungary, a traditional wine- and grape-producing country. The present study has revealed that some vineyards (e.g., inclination, row orientation) and variety features (e.g., bunch structure) were considered crucial. At the same time, other factors were found to be less relevant in the present complex comparison, suggesting that the role of these factors might be overemphasised in the literature. In conclusion, the susceptibility or tolerance of grapevines to pathogens appears to be an integrated effect of several factors and cannot be assigned to a single characteristic. The global changes urge the revision of conventional agricultural traditions and deepen our knowledge about the infection process and pathogen-host-environment interactions.

Plant pollens and fungal spores are massively produced in natural habitats and large‐scaled agricultural areas, and the airborne transported biomass can be accumulated on relatively large crop surfaces. A pollen grain contains a specific chemical composition in quantity and quality, highly varied among plant species. So, the accumulated pollens could provide a species‐specific nutrient supply for the initial fungal development in a pollen trap. Thus, this could increase the variation of the pathogen infection risk in certain plants due to selection mechanisms such as host–pathogen coevolution, crop breeding or pollination type. However, the role of the pollen‐stimulated spore germination and the species‐specific differences in the pollen‐spore interferences is still less understood. Therefore, we performed a multispecies experimental comparison (including 20 plant species) to test the role of the taxon‐specific attributes (i.e. host–pathogen compatibility, cultivation, pollination type and pollen size) in the dose and temporal response of the spore germination in Botrytis cinerea. We found a strong pollen‐stimulating effect on spore germination; however, the triggering effect highly varied among plant species and differed between specific functional categories across temporal and concentration gradients. Specifically, the B. cinerea hosts, the non‐cultivated plants and species with larger pollen size, increased the spore germination's stimulation effects, but not the pollination type. The systematic taxonomic and functional differences might reflect indirectly the diversity of the pollens' chemical profile (i.e. composition matrix or specific trigger molecules) which different selection mechanisms might shape. In the crop–pathogen interactions, the pollen‐stimulation effect could play an essential role in early fungal development.

‘Candidatus Phytoplasma prunorum’ is causing ever increasing economic losses through the decline of apricot trees in European countries, e.g., Hungary. In this study, the pathogen was identified from plant tissues and insects by nested-PCR. The insect species were identified via morphology and molecular methods. The incidence of the pathogen was 29.6% in randomly selected apricot trees. Most of the infected trees with symptoms died within a year. These results show that phytoplasma is significantly present and causes damage in the investigated plantations. The only known insect vector of this phytoplasma is the plum psyllid, Cacopsylla pruni, which was regularly encountered in the sampled apricot orchards and in their surroundings. In a two-year study, several adults among the sampled specimens were observed to be infected by the pathogen. This observation further confirms the role of the plum psyllid in vectoring the phytoplasma. All the sampled plum psyllid adults belonged to the ‘B’ biotype. Besides C. pruni, Cacopsylla crataegi was abundant in the samples. Several adults of the latter species were also infected by the pathogen ‘Ca. Phytoplasma prunorum’. The rates of occurrence of this phytoplasma in male and female adults of the two psyllid species appeared to be similar. The examined C. crataegi individuals showed genetic differences from each other and from specimens included in a previous investigation.

In some apricot growing areas in Europe, Asia and Africa, 'Ca. Phytoplasma prunorum' - the agent of European Stone Fruit Yellows (ESFY) - can cause significant economic losses in the stone fruit orchards. In the present study, 'Ca. Phytoplasma prunorum' infection of three apricot cultivars was evaluated by molecular methods in Hungary. We found the pathogen to be prevalent in the studied orchard (54%). We investigated the sensitivity of the apricot cultivars to ESFY. Trees were classified into disease categories based on the symptoms, and the number of dead trees was counted separately. From these data, the disease severity index and tree destruction index were calculated, and statistical comparisons of disease incidence were performed. Damage to ESFY can be reduced by using less susceptible cultivars because chemical plant protection is only effective against the vectors. The presence and infection of phytoplasma were mostly tolerated by the cultivar 'Zebra'. The 'Flavorcot' cultivar was moderately affected by ESFY, but the 'Sweetcot' cultivar was very susceptible. 'Ca. Phytoplasma prunorum' causes significant tree mortality; 44% of the trees molecularly confirmed to be infected had died by the end of the study. 'Zebra' had the lowest tree mortality (15%), while 'Sweetcot' had the highest (65.8%). Examination of the grafts planted as replacements showed that 3.3% of the plants were infected. The spread of diseased material can represent new sources of infection in orchards.

Blackleg (stem canker) of crucifers is a globally important disease caused by multiple genetic subclades of the fungi Plenodomuslingam (syn.: Leptosphaeria maculans) and Plenodomus biglobosus (syn.: Leptosphaeria biglobosa). In our study, we monitored the geographical distribution of these two pathogen species from rapeseed growing areas in Hungary. Multiplex PCR identified 48.7% of the isolates as Plenodomus biglobosus, which indicates the non-recent introduction of the pathogen into Hungary. In addition, multi-locus analysis revealed low genetic diversity within the species, as all isolates were clustered to the Plenodomuslingam ‘brassicae’ and Plenodomus biglobosus ‘brassicae’ subclades. The low genetic diversity of a population generally means reduced adaptation potential, which is essential information in breeding and in developing more effective management strategies.