Submitted to: Annual Cumberland Shenandoah Fruit Workers Conference
Publication Type: Proceedings
Publication Acceptance Date: January 15, 2004
Publication Date: October 1, 2004
Citation: Miller, S.S. 2004. Long-term use of apogee® for 'nittany' apple on m.9 rootstock - the first year 1. Annual Cumberland Shenandoah Fruit Workers Conference. Vol. 79, 7 pages. 2003 Interpretive Summary: Three-year-old 'Nittany'/M.9 apple trees were treated with three individual sprays of the growth regulator Apogee. The initial spray was applied at petal fall at 125 mg·L-1. At 2-wks and again at 4-wks after petal fall a second and third spray was applied each at 63 mg·L-1. Trees were hand thinned after "June-drop" to space fruit about 15 cm apart and to distribute crop load over the canopy. Fruit was harvested at the time of commercial harvest for the cultivar in the area and using flesh starch indexing ratings as a guide. Apogee treated trees had fewer fruit numbers and total fruit weight than control trees. Apogee treated fruit was also smaller, both in diameter and weight, than fruit from control trees. However, fruit from Apogee treated trees was firmer and had a higher starch index rating (meaning fruit was more mature) than control fruit. Growth measurements showed that Apogee decreased terminal shoot growth and reduced tree height, but had no effect on canopy spread or trunk cross-sectional area after the first year of treatment. Sprays will be applied each season during the next four years to determine long-term effects of repeated application of Apogee to apple trees.
Technical Abstract: Apple growers would like to use the growth regulator Apogee on younger fruit trees, but they have concerns about excessive growth control and the use of annual sprays on these trees. A study was initiated on 3-year-old apple trees using a lower dose multiple spray treatment of Apogee. Sprays will be repeated on the same trees each season over the next four to five growing seasons. This report provides information on the effects after the first year of treatment. Apogee reduced tree height and terminal shoot growth, but also reduced fruit size, increased fruit firmness, and lowered fruit starch levels at harvest. This information will benefit apple growers and extension fruit specialists who provide recommendations to the fruit industry.