DOI: https://doi.org/10.5513/JCEA01/26.1.4375
Original scientific paper
Features of the appearance of sunflower Septoria disease in the conditions of the Southern Steppe of Ukraine
2025, 26 (1) p. 114-125
Khrystyna Levytska, Viktor Lyakh, Anatoliy Soroka, Tetiana Rozhkova
Abstract
In recent years, Septoria leaf spot in sunflowers has become increasingly widespread in Ukraine. The research was conducted to establish the features of the appearance of Septoria leaf spot on sunflower plants in years with different levels of moisture availability and the possible development of this disease together with other foliar fungal diseases in the conditions of the Southern Steppe of Ukraine. Experiments were performed on a stationary infectious diseases plot of the Institute of Oilseed Crops of NAAS. It was established that the development of Septoria leaf spot on sunflowers was highly dependent on weather conditions. It was noted that the greatest damage to plants by Septoria leaf spot was at the beginning of the sunflower growing season in 2021, which was characterized by a record amount of precipitation. The first symptoms of Septoria leaf spot were noted in the middle or at the end of May on the cotyledon leaves. Lesions in the form of spots were up to 5 mm, rounded or uneven in shape. In the affected areas, pycnidia with pycnidiospores up to 65 μm in size and having up to 5 septa were identified. It was established that the appearance of the disease in breeding lines depended both on the level of their resistance and the weather conditions of the year. The number of affected plants in individual samples in 2021 reached about 100%. The severity of infection of experimental lines changed significantly under the influence of weather conditions. In resistant lines, the leaves of the lower or middle part of the plant were affected while in susceptible lines the symptoms of the disease were found on all leaves. It was established that in 2021 there were almost twice as many plants with damage to lesions on all leaves fall as in 2020. The possibility of simultaneous development of downy mildew and Septoria leaf spot on the same plant was revealed. In a year with an increased amount of precipitation, about 90% of plants affected by downy mildew were simultaneously affected by Septoria leaf spot. This indicates that these pathogens can develop on one plant and subsequently lead to a decrease in its main physiological functions.
Keywords
Septoria helianthi, weather conditions, symptom, frequency of infection, severity of infection, sunflower
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