Monitoring of the phytopathogenic state of sunflower crops in the Central Forest-steppe of Ukraine

The species composition of the causative agents of sunflower diseases was studied and the dominant species in the Central Forest-steppe were determined. Phytopathogenic monitoring of sunflower genotypes was carried out and the degree of prevalence and development of pathogens during the growing season was analyzed. The phytosanitary state analysis of sunflower agrocenosis was carried out during the growing season of 2021-2023. The phytopathological state of twelve sunflower hybrids was evaluated: SY Bakardi KLP, NK Kondi, SUZUKA, (Syngenta Crop Protection AG), LH5555 KLP, LH5580, LH59580 (Limagrain Europe), ES HENEZIS, ES Bellamis SL, ES AROMATIK SU (Euralis Semences), P64LP130, PR64F66, P64LE25 (Pioneer Overseas Corporation). The causative agents were identified: Phomosis (Phoma macdonaldii Boerema), Phomopsis (Phomopsis helianthi Munt.), white rot (Sclerotinia sclerotiorum (Lib.) de Bary.), gray rot (Botrytis cinerea Pers.), rust (Puccinia helianthi Schw.) and septoriosis (Septoria helianthi Ellis & Kellerm). In 2021, epiphytotia of gray rot was observed on sunflower. All hybrids were affected from 88.3% to 93.3 %. Rust damage reached 71.1 %. Resistant hybrids ES HENEZIS (13.3 %) and LH59580 (15.0 %) against rust were identified. Between 40.0 % and 50.0 % of sunflower hybrids were affected by septoriosis. Phomopsis infestation ranged from 27.2 % to 34.7 %. Not significant development of phomosis was noted from 5.0 % to 13.3 %. There was no white rot pathogen infection. In 2022 the intensity of sunflower hybrids damage by pathogens ranged from a low of 6.7 % to an average of 45.0 %. Gray rot infestation ranged from 41.7 % to 45.0 %. The development of white rot was not significant, up to 10%. Infection of the hybrids by the causative agent of septoriosis was at the level of 20.0– 25.0 %. High resistance against white rot was noted in the P64LP130 hybrid. ES HENEZIS and LH59580 hybrids were resistant to rust. Phomopsis damage (up to 15 %) was noted in hybrids NK Kondi, LH5580 and ES AROMATIK SU. All studied hybrids showed resistance and moderate resistance to phomosis. In 2023 weather conditions were not conducive to the pathogens development. Phomosis acquired the highest development (up to 30.0 %) on sunflower hybrids. The development of gray rot and septoriosis was not detected. The development of rust pathogen was absent on sunflower hybrids, except for two ones. High resistance against Phomopsis was shown by NK Kondi, ES AROMATIC SU and LH5580 (1.7 %). High resistance against white rot was noted in the P64LP130 hybrid. Key words: sunflower, hybrids, disease monitoring, phomosis, phomopsis, white and gray rot, rust, septoriosis.