Thesis for a scientific degree of a candidate of agricultural sciences (doctor of philosophy) in specialty 06.01.11 - phytopathology. – Institute of plant protection of National academy of agrarian sciences of Ukraine, Kyiv, 2020; Kharkiv National Agrarian University named after V.V. Dokuchaiev. – Kharkiv, 2020.
In the dissertation the composition of the complex of turfgrass diseases in Polissya, Forest-steppe and Steppe of Ukraine was determined and the features of its formation were investigated.
It has been established that species composition of the pathogens of turfgrass diseases consists from the following: powdery mildew (causal agent Erysiphe graminis), septoria leaf blotch (Septoria tritici), brown spot (Bipolaris sorokiniana), sharp eyespot (Rhizoctonia spp.), yellow rust (Puccinia striiformis), slime mold (Physarum cinereum), pink snow mold (Microdochium nivale). The most common disease of lawn grasses in Polissya is powdery mildew, the proportion of which in the complex of diseases was 31.3%, in Forest-Steppe – powdery mildew and slime mold, the dominance of yellow rust was observed in the steppe zone.
Slime mold (causal agent - myxomicete Physarum cinereum Batsch.) was noted on turfgrasses for the first time in Ukraine. The most widespread disease was in the forest-steppe zone, where its development reached 21.2%. It was established that Zymoseptoria tritici (Roberge ex Desm.) Quaedvl. & Crous is a causal agent of septoria leaf blotch of turfgrasses under conditions of Ukraine.
It is proved that the duration of the snow cover is the key abiotic factor affecting the manifestation of pink snow mildew. Significant linear dependence between them was found (correlation coefficient is 0.749) and it has been established that the disease developed when the duration of the snow cover exceeds 39 days. There is also a tendency of increase of disease severity with rise of maximum height of snow cover.
Pathogenic mycoflora of grass seeds consists of representatives of genera Alternaria, Fusarium, Bipolaris, Penicillim, Aspergillus. Domination of Alternaria spp. and Fusarium spp. was established. The phytopathological analysis of two mixtures of turfgrasses has shown that the sowing quality is related to the level of infection by microorganisms.
It has been established that agrotechnical measures have a multi-vector impact on the development of diseases of turfgrasses. It has been shown that fertilization with nitrogen fertilizers increases the growth of powdery mildew severity by 5-6 times, septoria leaf blotch and yellow rust – twice as much as control. The highest level of disease severity was found on plots where nitrogen was applied with the dosage N50 and N75 at a lower frequency of mowing. For more frequent fertilization (every 15 days), 100% of the projective coating was formed, as opposed to 60% in the control. Mowing every 7 days led to decrease in the disease severity compared with the variants, where this practice was carried out once every 14 days, for powdery mildew - 2-5 times, septoria leaf blotch and yellow rust - in 1,2-1,5 times. The application of complex fertilizers contributed to the development of powdery mildew and yellow rust.
Aeration, scarification and verticutting helped to reduce the development of all studied diseases. The efficiency of their complex application was more than 70% compared to control.
The best results against leaf diseases were obtained for the application of Alto Super 330 EC (0.5 l/ha), Amistar Gold 250 SE (12 ml/5 l of water per 100 m2) and tank mixture of Maxim 025 FS (0.75 l/ha) + Horus 75 WG (0.6 kg/ha). Technical efficiency against powdery mildew in these variants was 84.8-92.6%, septoria leaf blotch - 74.5-82.1%.
The efficiency of spraying of leaf surface of plants of turfgrasses in the late autumn period against pink snow mold has been proved. Maximum protection of the crop was ensured by spraying with a mixture of fungicides Maxim 025 FS and Horus 75 WG. Their efiiciency was at the level of 85.3-91.5%.
On the basis of the generalization of the experimental data obtained, a system of protection of lawn grasses from diseases was developed. It includes the complex application of agrotechnical measures, two-time spraying with fungicides against leaf diseases and autumn treatment for preventing the development of snow mold. According to the results of field tests carried out in 2017/2018, it constrains the development of diseases at low level (0.2-3.3%) and the formation of a lawn with a 100% projective coating.
Calculations of economic effect confirm the practicabilityof the application of the developed system of protection. The profit from its adaptation amounted to 164554-227259 UAH/ha, the profitability of the system was 190,5-259%.
