Woody plants at urban greeneries in Lithuania are injured by rust fungi of 13 genera, 28 species: Coleosporium pulsatillae, C. tussilaginis, Cronartium flaccidum, C. ribicola, Cumminsiella mirabilissima, Gymnosporangium clavariiforme, G. confusum, G. cornutum, G. sabinae, G. tremelloides, Hyalopsora aspidiotus, M. allii-fragilis, M. allii-populina, M. caprearum, M. epitea, M. laricis-populina, M. populnea, Melampsora ribesii-viminalis, M. salicis-albae, Melampsorella caryophyllacearum, Melampsoridium betulinum, M. carpini, Ochropsora ariae, Phragmidium tuberculatum, Pucciniastrum areolatum, P. symphyti, Uromyces caraganicola, U. pisi-sativi. During 2009 – 2017 Gymnosporangium sabine had the strongest damages (from 0.21 ± 0.00 to 2.43 ± 0.33 grades) on Pyrus pyreaster, the weakest damages had done G. cornutum on Sorbus intermedia and S. x thuringiaca ‘Fastigiata’ – 0 – 1 ± 0.58 grades.

Rhododendron spp. plants were surveyed for Phytophthora infection in Lithuania during 2010 – 2016. This study aims to identify Phytophthora genus pathogen which infects rhododendrons in Lithuania. Samples were taken from young sick plants with visible infection symptoms. Soil sampling was performed from the rhizosphere of sick plants. DNA from soil and plant was tested for the presence of Phytophthora genus pathogens. Data showed positive results of Phytophthora genus specific probe during real-time PCR. All tested diseased leaves and soil samples have indicated Phytophthora sp. infection during Alert-LF® Phytophthora spp. analysis. The extracted DNA concentrations were not very high for Phytophthora species identification, but in most cases, it was high enough for further researches.

Japanese quince (Chaenomeles japonica) is cultivated as a fruit crop because its fruit possesses valuable properties. The total area of Japanese quince in Latvia is continuously increasing; therefore, fruit rot can become an important reason of yield loss. The aim of this study was to clarify the fruit rot incidence in Japanese quince plantations in Latvia and explore the influencing factors of rot development in the year 2017. The evaluation of fruit rot was carried out during the fruit development in eight places of different regions of Latvia where Japanese quince is grown commercially. Three plantations of different Japanese quince cultivars in Dobele and seven plantations where Japanese quince is grown from seedlings were observed. Fruit rot incidence among plantations had no significant differences. Statistically significant differences in fruit rot incidence depending on quince growth stage (p is less than 0.05) were found. Significant differences in fruit rot incidence were found between cultivars in Dobele.

Potato is the second important crop in Latvia. The area covered with potato is about 50 thousand hectares. Potato late blight caused by Phytophthora infestans (Mont.) de Bary is the most serious potato disease. Weather conditions in Latvia are very favourable for the development of potato late blight and it is occuring almost every year. The biology of P.infestans was the subject of a number of authors - plant pathologists. Research results about P.infestans population biology and epidemiology are presented in this review, especially focusing on the changes of pathogen biology.