EFFECT OF METHOD OF APPLICATION OF PACLOBUTRAZOL IN HIGH-DENSITY SWEET CHERRY ORCHARDS ON TREE PERFORMANCE AND APPARENT SOIL RESIDUE

SummaryFour year old `Bing' sweet cherry trees planted at a density of ca. 1500 trees per ha were treated once with paclobutrazol (Cultar) applied as soil drench (SD) where 1 l of paclobutrazol aqueous solution was poured into a furrow around the tree trunk, or applied as a row-side drench (RSD) where 1 l of paclobutrazol solution was divided into two doses of 0.5 l and poured into two furrows located on both edges of the herbicide strip, or a bark painting application (BP) where a 20 cm wide tree bark band was brush-painted with paclobutrazol dissolved in 100% `Surfactant WK'. A standard rate 15 mg paclobutrazol per cm2 of tree trunk cross-sectional area was applied in all three cases. The SD and RSD trees showed signs of shoot growth inhibition 69 d after application, about 12 d before some inhibition was seen on the BP trees. Fruit set was reduced by both the SD and RSD but not by the BP. Yields were not influenced by paclobutrazol in the application year. The highest two-year cumulative yields were ob...