The study of phytophages and phytopathogens adapted to invasive species Helianthus tuberosus L. and H. subcanescens (A. Gray) E.E. Wats. (Asteraceae) was conducted in 2022–2023 in Moscow and Kaluga regions. The identification of collected samples was carried out in the plant protection laboratory of the Main Botanical Garden of RAS. Three species of phytophages were found that occur sporadically and do not cause serious damage to plants. These species are generalized polyphages; we have not found specialized phytophages. The powdery mildew pathogen of sunflower, namely Erysiphe cichoracearum DC. f. helianthi Jacz. was the most adapted to invasive Helianthus species. Other pathogens were not detected in invasive populations due to the relative resistance of latter to phytopathogens and unfinished process of consortial relationship formation.

A.V. Stogova, A.N. Shvetsov, A.G. Kuklina, O.A. Kashtanova, O.B. Tkachenko