The effectiveness of three-component fungicides based on first and second class sterol biosynthesis inhibitors against leaf diseases of spring wheat

In the Leningrad region, regardless of the norm and frequency of use, high biological efficacy of drugs (83.7–100%) against powdery mildew, brown rust and mottling (dark brown and septoria pyrenophorosis) of leaves was noted. In the Saratov and Volgograd regions, a different trend was observed against brown rust and powdery mildew. The advantage was due to the two-fold use of drugs, while the most acceptable drug was “Soligor, CE” at the rates of 0.4 + 0.6 l/ha and 0.4 + 0.8 l/ha. The effectiveness of the drug “Falcon, CE” against powdery mildew was 81.3–100%, and “Soligor, CE” in the above-mentioned regulations was 70.1–93.3%. Double treatments with these three-component fungicides were 74–93.3% effective against brown rust. In terms of the mass of 1,000 grains and the mass of grain per ear in all regions where the biological efficacy of “Falcon, CE” and “Soligor, CE” preparations was studied, the advantage was for their double use. The double use of the drug “Falcon, CE” allowed to save from 8.8 to 38.3% of the crop, and the fungicide “Soligor, CE” — from 10.2–27.5 to 11.6–32.5% at application rates of 0.4 + 0.6 l/ha and 0.4 + 0.8 l/ha. According to the toxic load, both drugs are classified as moderately dangerous. With a close indicator of the hazard coefficient for bees (1.94–3.89), the environmental load of the drug “Falcon, CE” (11,963.43 units) was higher than that of “Soligor, CE” (1839.1–3677.2 units).