Turnip yield in open soil conditions in Polissya under different plant protection systems

The aim of the study was to evaluate the effectiveness of bacterial and chemical preparations regarding their impact on turnip yield and specific quality indicators of its root crops under different plant protection systems. The research was conducted at the Volyn State Agricultural Research Station of the NAAS in 2024-2025 using the turnip varieties ‘Zolota Kulya’, ‘Purpurova’, ‘Purpletop’, and ‘Geisha’. To protect against diseases, the chemical fungicide Magnicur Boost and the biological products Phytocide-r and Mycohelp (BTU company) were applied; for pest protection, the chemical insecticide Confidor Maxi and the biological products Bitoxibacillin-BTU and Aktoverm-formula (BTU company) were used. An untreated variant served as the control. The study was established with fourfold replication following standard vegetable-growing methodology. The results showed that the application of the biofungicide Phytocide-r increased the root crop yield of the ‘Purpletop’ variety to 22.2 t/ha, and for the ‘Zolota Kulya’, ‘Purpurova’, and ‘Geisha’ varieties (using Phytocide-r or Mycohelp) by 0.9-1.2 t/ha. Magnicur Boost and Phytocide-r increased the starch content in ‘Zolota Kulya’ root crops to 7.12-7.30% and vitamin C to 19.3-19.5 mg/100 g. The ‘Purpletop’, ‘Geisha’, and ‘Purpurova’ varieties proved to be more resistant to downy mildew; Mycohelp limited the spread of the disease to 2.0-2.7% and its development to 0.21-0.31%, while Magnicur Boost limited the spread to 0.76%. The systemic use of the bioinsecticides Bitoxibacillin-BTU and Aktoverm-formula increased the yield of the ‘Purpletop’ and ‘Purpurova’ varieties to 21.6-22.0 t/ha, whereas Confidor Maxi only increased it by 5%. Without insecticidal protection, the yield was at its lowest. Biological products increased the dry matter content to 16.3-16.4%, starch to 6.29-6.74%, protein to 5.4%, and vitamin C to 19.2-19.3 mg/100 g. Bitoxibacillin-BTU and Aktoverm-formula proved to be more effective against the adults of the black crucifer flea beetle