TROPHIC RELATIONSHIPS OF PHYTOPATHOGENS WITH CULTIVATED AND INVASIVE SPECIES OF THE GENUS HELIANTHUS (ASTERACEAE)

The aim of the study is to investigate the trophic relationships between phytopathogens and some species of the genus Helianthus L. (Asteraceae). Objectives: to analyze literature data on diseases of Helianthus annuus and H. tuberosus, and to conduct our own research on invasive populations of H. tuberosus in the regions of Central Russia. The species H. annuus and H. tuberosus were studied during field trips from July to October 2022–2024 in Moscow, the Moscow Region (Balashikha, Orekhovo-Zuyevo), and the Kaluga Region (Maloyaroslavets). Plant samples with signs of disease were analyzed in the laboratory of the Main Botanical Garden of the Russian Academy of Sciences using standard "wet chamber" and "pure culture" methods. Downy mildew Plasmopara halstedii, affecting H. annuus agrocenoses, is actively spreading in the regions of Russia. Puccinia helianthi rust is present on H. annuus everywhere sunflowers are grown, especially in America, Germany, Italy, Sweden, and Romania. This plant pathogen is found on sunflower plants in the Tambov, Saratov and Krasnodar Regions and poses a potential threat to species of the genus Helianthus. The study results showed that H. annuus and H. tuberosus share a number of common phytopathogens: Puccinia helianthi, Alternaria alternata, Botrytis cinerea, and Plasmopara halstedii, which are capable of forming trophic relationships with both plant species. Invasive populations of Central Russia were ubiquitous in late summer with the sunflower powdery mildew pathogen Erysiphe cichoracearum DC. f. helianthi Jacz. Sclerotinia sclerotiorum and S. nivalis, which cause white rot, were occasionally detected among naturalized Jerusalem artichoke plants. The limited species composition of these pathogens is explained by the fragmented nature of populations in the secondary range. This situation also characterizes the initial period of trophic relationship development in invasive populations of Helianthus species.