Ailanthus altissima (Mill) Swingle commonly known as tree of heaven was brought to Hungary as an ornamental tree between 1841-43 and became widespread in the country in the middle of the 20th century. Due to its ability to transform its environment and reduce biodiversity it became one of the most dangerous invasive plant species in Hungary (Udvardy and Zagyvai 2012). Verticillium wilt of A. altissima has been reported in the USA (Rebbeck et al. 2013; Snyder et al. 2013) and in Europe (Maschek and Halmschlager 2017) in the last few years. According to these studies, two Verticillium species can cause wilt symptoms on A. altissima: Verticillium nonalfalfae (formerly Verticillium albo-atrum) and Verticillium dahliae. During the summer of 2016, dying A. altissima trees were observed in Nyíregyháza (northeastern part of Hungary) and in several parts of Budapest that exhibited wilt symptoms, defoliation and yellowish vascular discoloration. To identify the causal agent, samples were collected from symptomatic ...

‘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.

Apricot is an important fruit crop in Hungary. There are large growing areas consisted of orchards of different sizes. These orchards are highly affected by a disease complex the so cold apoplexy with its characteristic symptoms. In this study, the effect of rootstocks and scion varieties on the severity of symptoms was investigated in an apricot orchard near Budapest. Symptoms were assessed in autumn at their most characteristic appearance on the combinations of 5 different scion varieties and 3 different rootstocks in 3 consecutive growing seasons. According to the results of the assessments in most cases, symptoms proved to be more frequent and stronger on trees grown on wild apricot rootstock than on plum intergrafted or myrobalan rootstocks. The variety Mandulakajszi proved to be consistently the least affected variety particularly on plum intergrafted rootstocks. Severity of symptoms observed on other investigated varieties deviated depending on the different rootstocks and growing seasons. To reduce the effect of growing seasons monitoring should be continued.