o:37440 Sclerotinia Species Causing Lettuce Drop Disease in Serbia en Sclerotinia spp. are globally distributed, devastating plant pathogens with a broad host range, including lettuce, on which they cause lettuce drop disease. To investigate the geographical distribution of lettuce drop incidence and the population structure of Sclerotinia sclerotiorum and S. minor in Serbia, 27 commercial lettuce fields across 12 administrative districts were surveyed. Sclerotinia spp. were confirmed at 10 localities, with S. sclerotiorum occurring more frequently. Co-occurrence of both species within the same field was recorded at only one location. Clear phenotypic and physiological differences were found between Sclerotinia species, as well as among isolates within each species. The two species differed in colony appearance, sclerotia production, virulence, growth rate, oxalic acid production, and tolerance to elevated osmotic pressure. Haplotype analysis of S. minor revealed the existence of 9 haplotypes arranged in a star-shaped network. These findings highlight the importance of considering both inter- and intraspecific variability of Sclerotinia species when evaluating their impact on crops, improving our understanding of Sclerotinia populations in lettuce, and supporting the development of effective management strategies. Lactuca sativa; morphological characterization; pathogenicity; virulence; phylogeny; Sclerotinia sclerotiorum; Sclerotinia minor; oxalic acid 1552099 https://doi.org/10.3390/microorganisms14010189 2026-01-14T15:17:17.087Z 44 no 46 Maja Živanović Institute of Pesticides and Environmental Protection, Banatska 31b, 11080 Belgrade, Serbia Milica Mihajlović Institute of Pesticides and Environmental Protection, Banatska 31b, 11080 Belgrade, Serbia person Aleksandra A. Jovanović University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor tehnoloških nauka person 0000-0001-5394-0125 Jovana Hrustić Institute of Pesticides and Environmental Protection, Banatska 31b, 11080 Belgrade, Serbia person Mira Vojvodić Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia person Brankica Pešić Institute of Pesticides and Environmental Protection, Banatska 31b, 11080 Belgrade, Serbia person Aleksandra Bulajić Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia person application/pdf 2511591 https://phaidrabg.bg.ac.rs/o:37440 no yes 16 70 92000001 11A29 11A2910 11A33 Sclerotinia Species Causing Lettuce Drop Disease in Serbia 189 14 1 Microorganisms Basel, Switzerland MDPI 2026