Colletotrichum orbiculare on watermelon: Identification and in vitro inhibition by antagonistic fungi

Anthracnose caused by the fungus Colletotrichum orbiculare is one of the most significant diseases of Cucurbitaceae. In Serbia watermelon fruits with typical anthracnose lesions were collected during the year of 2015. Affected fruits showed sunken, dark brown to black lesions with orange conidial masses produced in black acervuli. In an attempt to identify the causal organism, small pieces of necrotic tissue were surface sterilized and placed on potato dextrose agar (PDA). Macroscopic and microscopic morphologicaly characteristics of three isolates were observed after growth on PDA for 7 days at 25 ºC under a 12 h light/dark cycle. Fungal colonies developed white, grey to black dense aerial mycelium. Conidia were hyaline, aseptate, straight and cylindrical to clavate, 9–12.5 μm × 4–5.5 μm. Fungal isolates were also characterized by sequencing of the internal transcribed spacer (ITS) rDNA region using ITS1F/ITS4 primers and β-tubuline 2 gene using T1/Bt2b primers. The nucleotide sequences were deposited in GenBank (ITS Acc. No. KT454386, KT454387 and KT454388; β-tubuline 2 gene Acc. No. KT581236, KT581237 and KT581238). BLAST analysis of ITS and β-tubuline 2 gene sequences showed that our isolates were 100% identical to other C. orbiculare in NCBI GenBank. Pathogenicity test was conducted on symptomless, detached watermelon fruits. All tested isolates caused anthracnose lesions on watermelon fruits after 10 days of incubation. Trichoderma harzianum (DSM 63059) and Gliocladium roseum (DSM 62726) were evaluated in vitro for their antagonistic potential against C. orbiculare. The results of this study identify T. harzianum and G. roseum as promising biological control agents (BCAs) for further testing against anthracnose disease on watermelon fruits

Comprehensive qualitative evaluation of the first ever full-time online course for medical students in one middle-income country

ABSTRACTThe measures to control the COVID-19 pandemic in the academic 2020/2021 included full-time online courses for medical students in Serbia for the first time since the faculty was founded in 1920. The purpose of this study was to examine the attitudes and opinions about the full-time online course among medical students and their teachers. A qualitative study was carried out in the autumn of 2021. In-depth interviews were conducted with 38 participants (27 students in the 4th study year and 11 teachers who teach in the 3rd study year) about their experiences in the past academic year. To select study participants, purposive sampling was employed. The interviews were audio-recorded and transcribed verbatim. Qualitative content analysis was applied. Five topics emerged: 1) Theoretical online learning, 2) Practical online learning, 3) Motivation, 4) Technical aspects of online learning and 5) Evaluation of knowledge. Overall, students’ attitudes toward theoretical classes were mostly negative, but the attitudes of teachers were mostly positive. However, the attitudes of both students and teachers toward practical online classes were mostly negative. Students were, in general, less motivated to follow online classes compared to conventional courses, even though the teachers felt that they had to put more effort into making a suitable online course. Most participants considered that the online classes had a negative impact on their knowledge and practical skills, but their academic achievement was not inferior compared to previous years. The full-time online course should include conventional on-site teaching. The relevance of acquiring practical skills is strongly emphasized