Quality deposit of phytopharmaceutical product is necessary to achieve high yield of potato. In order to achieve precise and quality spray deposit the anti drift nozzles TurboDrop® VR 2 HiSpeed were used in the field trial in Laboratory field of Biotechnical Faculty in Ljubljana. There is almost linear relationship between volume flow rate and spray pressure when using these nozzles. The recommended spray pressure is between 2 and 8 bars. In the trial contact insecticide Alverde (a.i. metaflumizon) was used for the chemical control of Colorado potato beetle (Leptinotarsa decemlineata). The following spray pressures and volume rates were applied: 2.0 bar and 204 l/ha, 3.0 bar and 302 l/ha, 4.0 bar and 348 l/ha, 5.0 bar and 454 l/ha. The aim of field trial was to determine coverage value, droplet impression number per square centimeter and tuber yield. Spray deposit quality was determined by the use of water spray papers, which were attached to the upper, middle and lower part of the potato plant. It was established that the most suitable spray pressure for the quality spray deposit of contact insecticide was 5.0 bar, while the lowest spray coverage was achieved at spray pressure of 2.0 bar. Coverage value decreased from the top to the bottom of potato plant. The droplet impression number per square centimeter was the lowest at spray pressure of 5.0 bar. On the control parcel the tuber yield was smaller regarding the parcels sprayed with different spray pressures.
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