Chemical thinning of apple blossoms in organic production | Kemijsko prorjeđivanje cvjetova jabuke u ekološkoj proizvodnji

English. An experiment on chemical blossom thinning on apple variety 'Summerred'/ M9 was performed in an experimental plantation in Brdo pri Lukovici. Different chemical thinners were applied on apple’s fruitlets in organic production. The experiment was designed in 7 randomized block with 13 treatments: 1. unthinned trees (as a control), 2. hand thinning in June, 3. 1% NaCl, 4. 1,5% NaCl, 5. 1% CH3COOH, 6. 3% CH3COOH, 7. 3% CaSx, 8. 1% rape oil, 9. 3% rape oil, 10. 3% of sunflower oil, 11. 3% soybean oil, 12. 5% dextrin, 13. emulsifier 100 + OCA 30. Chemical thinners were applied in a phenological stage at peak blooming with a manual knapsack sprayer. The best thinning of fruitlets (similar to hand thinned trees) was observed with 3% rape oil, however, relatively strong russeting of fruit skin was detected in this treatment. Statistically significant reduction of final fruit set also occurred when 1,5% NaCl and 3% soybean oil were applied, but with less fruit russeting.

Croatian. Na eksperimentalnoj plantaži (Brdo pri Lukovici) proveden je pokus kemijskog prorjeđivanja cvjetova jabuke sorte ‘Summerred’ cijepljene na podlozi M9. Cilj eksperimenta bio je ispitati učinke različitih sredstava koji se koriste u jabukama u ekološkoj proizvodnji. U pokusu sa 7 randomiziranih blokova i 13 tretmana proučavan je utjecaj: 1. neprorijeđeno, 2. ručno rijeđeno u lipnju, 3. 1% NaCl, 4. 1,5% NaCl, 5. 1% CH3COOH, 6. 3% CH3COOH, 7. 3% vapneni sumpor CaSx, 8. 1% ulje uljane repice, 9. 3% ulje uljane repice, 10. 3% suncokretovo ulje, 11. 3% sojino ulje, 12. 5% dekstrin, 13. emulgator 100 + OCA 30. Kemijski prorjeđivači primijenjeni su u fenološkom stadiju u vrhuncu cvjetanja. Najbolje prorjeđivanje plodova, slično onima s rukom, zabilježeno je pri nanošenju 3% ulja uljane repice. Prilikom ovog tretmana uočena je razmjerno jaka rđavost kože ploda. Statistički značajna manji broj plodova također se pojavilo kada je raspršeno 1,5% NaCl i 3% sojinog ulja, ali s manje izraženom rđavošću jabuka.