Spring wheat is a leading grain food crop . It is one of the first grain crops as to sown areas and gross grain harvest in the world. Increasing its production and improving its quality remain the main task to solve the food problem. Within recent years a significant attention has been paid to spring wheat. This is due to both the growing market demand of this crop for grain and the use of its seeds when winter crops are resown. In 2019 in Ukraine its sown area was 478 thousand hectares, and in 2017 - 167 thousand hectares.
In 2018, the sown area of spring wheat in Ukraine was 175 thousand hectares, particularly in Kharkiv region - about 7 thousand hectares. One of the factors that significantly reduces spring wheat productivity are diseases of fungal etiology. Spring wheat is affected by about 60 pathogens. It reduces its productivity up to 15%.
Powdery mildew, septoriosis and brown leaf rust were found to be the most widespread and harmful diseases of leaves spring wheat in the Eastern Forest-Steppe of Ukraine.
For the first time the models of short term prognosis concerning powdery mildew, septoriosis and brown leaf of spring wheat leaves depending on the air temperature and air humidity amount were worked out for the conditions of the Eastern Forest-Steppe of Ukraine.
The determined cycle in the development of the pathogenic organism is extremely important. It was ascertained that the first visible signs of powdery mildew appeared in the form of spots, with a white spider bloom. 2−3 days pacted on the leaf plate, sporebearing and turned into wadding pads – conidial. Since septoriosis infection until the first visible disease symptoms appeared on the average 10−14 days passed. The incubation period of brown leaf rust development lasted from 7 to 21 days. Twelve to nineteen days later after the appearance of ureidia on the mycelium, tubers with teliospores were formed.
The heaviest infection of plants with disease pathogens was observed at the optimum average daily temperature (14−20 °C) and increased daily average air humidity (60−70 %). Depending on the meteorological conditions of the vegetation and the resistance of the varieties, the disease development was: for powdery mildew − 19,9−21,3 %, septeriosis of leaves − 19,7−22,4 %, brown leaf rust − 1,8−2,9 %.
The influence of chemical and biological agents differing in the active substance and the mechanism of influence on the growth and development of septoriosis pathogens, powdery mildew and brown leaf rust of spring wheat was determined.
The highest efficiency of fungicidal preparation Serticor 050 FS, s.c.c. with a consumption rate 1 l/t to protect against leaf diseases of spring wheat.
The efficiency of spraying wheat wheat crops in the bushing out stage at the beginning of the pipe formation process was determined by using Amistar Trio e.c. with the consumption rate 1 l/ha, which reduced the prevalence and development of powdery mildew and septoriosis by 2 times compared with the control and productivity amounted to 4,2−4,6 t/ha.
The use of biopreparations Phytosporin-M, Imunotsitophyt, Bactophyt, Pseudobacterin significantly influenced the productivity of spring wheat. Thus, when the biological preparations were applied spring wheat productivity ranged from 4,2 to 4,6 t/ha in all variants, while the control one was 3,7 to 3,9 t/ha
The efficiency to use Phytosporin-M with the consumption rate 1 l/ha in protection against leaf diseaseswas proved. The productivity increase was 0,35 t/ha compared with the control.
The economic fexpediency of using Amistar Trio e.c. (1 l/ha) and Phytosporin-M (1 l/ha) to limit the development of major leaf diseases in spring wheat was found it ensured a conditional net profit of UAH 1143,15 and UAH 2638,6 when a profitability levelamounted 265 % and 274 %. Using these preparations the productivity increase was 0,35 t/ha and 0,81 t/ha relativety to the control.
