Effect of modern fungicides on severity of diseases of spring barley

Goal. To carry out monitoring of spring barley diseases and determine the technical efficiency of modern fungicides during the vegetation period. Methods. The observations of disease severity were performed according to conventional methods. The technical efficiency of fungicides was studied in the Kyiv region, Belotserkovsky district, EB Alexandria in 2017—2018 under the conditions of natural infection on the cv. Commander. The size of the plots — 10 m2 in 4 replicates, the placement of plots — randomized. Agrotechnics are common for the growing area. Before the first application, an observation was carried out to establish the presence of diseases and their severity. In 15 days after the treatment with fungicides, records were taken to determine the development of the disease. Two treatments were performed with fungicides: the first at the flag leaf stage (39 stage on BBCH scale), the second — at booting stage (49 stage on BBCH scale). The following fungicides were tested: Aviator Xpro 225 EC, 0.8 l/ha, Acanto Plus 28 SC, 0.75 l/ha, Amistar Extra 280 SC, 0.75 l/ha, Abacus ES, 1.75 l/ ha, Bontima 250 EC, 2.0 l/ha. Results. During the period of investigation, the following leaf diseases were the most common:net blotch (Pyrenophora teres Drechsler), brown spot (Bipolaris sorokiniana Shoemaker) and powdery mildew (збудник Blumeria graminis (DC.) Speer). The efficiency of fungicides against leaf diseases of spring barley was established. It was: against net blotch — 75.7—87.0%, brown spot — 70.0—80.0%, powdery mildew — 78.0—100%. The fungicide application made it possible to save a considerable part of the yield. The preserved yield at application of fungicides reached 0.18—0.27 t/ha. In the variants with the fungicides, the weight of 1000 grains increased by 3.3—4.4 g. A significant difference was observed between the variants and control over the parameters of the mass of 1000 grains. Conclusions. In the 2017 and 2018 growing seasons in the Kyiv region, the complex of spring barley leaf diseases included: net blotch (Pyrenophora teres Drechsler), brown spot (Bipolaris sorokiniana Shoemaker) and powdery mildew (збудник Blumeria graminis (DC.) Speer). It is noted that for the protection of spring barley leaves it is advisable to apply one of the fungicides: Aviator Xpro 225 EC, 0.8 l/ha, Acanto Plus 28 SC, 0.75 l/ha, Amistar Extra 280 SC, 0.75 l/ ha, Abacus ES, 1.75 l/ha, Bontima 250 EC, 2.0 l/ha. The use of fungicides made it possible to protect the top two leaves from infection during grain filling, whach had a positive effect on the formation of structural elements, plant productivity and on quantitative and qualitative parameters of the yield.