The article represents the results of research for 2016–2018 in the condition of Western Forest-Steppe of Ukraine. The yield of winter barley obtained under various fungicide treatment and three diff erent fertilization dose rates of (N40P30K40, N80P60K80, N120P90K120) was compared in the study The influence of mineral fertilizers on the diseases development was studied along with fungicides application effi ciency for the following diseases of Wintmalt variety of winter barley: net blotch, powdery mildew, and spot blotch. Three major diseases were observed in barley crops during the research years: net blotch, powdery mildew and spot blotch.
It has been established that increasing the level of fertilization contributes to the increase of disease development in barley crops. Thus, the highest level of net blotch (51.7 %), spot blotch (15.4 %) and powdery mildew (17.5 %) was observed on the variant of N120P90K120. High effi ciency of the studied fungicides was established. The highest technical effi cacy of the preparations was obtained on the variant of Systiva 1,5 l/t + Adexar Plus 1,0 l/ha in the stage of the fl ag leaf.
The results of the studies showed that the highest yield (9.27 t/ha) of the Wintmalt variety of winter barley under the studied conditions was obtained on the variant of complete mineral fertilization N120P90K120 and the treatment of fungicide plant protection by Systiva 1.5 l/t (BBCH 00) + Adexar Plus (BBCH 39) 1.0 l/ha.
The fungicide protection of Systiva applied to the seeds along with the pre-sowing treatment, ensured a yield increase of 0.64 t/ha, 0.68 t/ha and 0.77 t/ha on the N40P30K40, N80P60K80, N120P90K120 respectively. The highest yield increase compared to the control was obtained on the Systiva 1.5 l/t (BBCH 00) + Adexar Plus (BBCH 39) 1.31–1.69 t/ha depending on the dose rates of fertilization. Fungicide protection is recommended to apply to all the studied fertilizers dose rates, but the highest yield increase from the fungicides was obtained on N 120P90K120.
Key words: winter barley, fungicide, Systiva, Abacus, Adexar Plus, disease, fertilizers, yield.