The field trial was executed in 2020 with the variable flow rate nozzle TD VR 1.5 and contact pyrethroid for the control of cereal leaf beetle (Oulema melanopus [L.]). Three different winter wheat cultivars – 'Falado', 'Gorolka' and 'Illico' – were used in the trial. The spraying pressure was 2 bar, 4 bar and 6 bar providing the water rate of 117 l/ha, 207 l/ha and 271 l/ha, respectively. The coverage and arrangement of droplets on the flag leaf and the lower lying leaf were examined with water sensitive papers. The leaf area damage was evaluated and the winter wheat yield analysed. The coverage value and the droplet imprint number rose as the spraying pressure was increased from 2 to 6 bar, both on the flag leaf and the lower lying leaf regardless of wheat variety. The percentage of leaf area damaged by the cereal leaf beetle was higher for the 'Gorolka' variety than for the other two varieties. There was no difference in leaf area damage between the respective spraying pressures of 2, 4 and 6 bar, while the highest leaf damage was found on the control lot (unsprayed). Grain yield also remained unchanged with different spraying pressures. Both the grain yield and the absolute grain weight were significantly lower on the control lot for the Gorolka variety compared to the other two. Results show that a comparable grain yield can be achieved at a lower spraying pressure of 2 bar with contact pyrethroid and a lower water rate of 117 l/ha compared to higher spraying pressures of 4 and 6 bar and the accompanying higher water rates.
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