Apogee® (porhexadione calcium)
Apogee is a plant growth regulator that has the ability to eliminate the production of gibberellins (GAs) in apple trees. This reduction in the level of GAs reduces the rate of shoot growth. This effect may reduce pruning costs, increase the red color of apples when light in the tree is limiting, make the tree canopy easier to spray, and aid in the control of some disease and insect pests. Apogee is also labeled for the control or reduction of fire blight in apples. Apogee is recommended to be applied when shoot growth is about 1 to 3 inches in length. This period usually occurs around petal fall. Rates are 3 to 12 ounces/100 gallons on a dilute basis or 9 to 36 ounces per acre, depending on the vigor and crop load of the trees. In south-central Pennsylvania, most growth occurs in May and June, so two to four applications may be needed to get season-long shoot growth suppression. It takes about 10 to 14 days for Apogee to have an effect on growth, and the growth suppression lasts for about 2 to 4 weeks. Significant regrowth may occur in the tops of trees when sprays are terminated too soon or where spray coverage is poor.
You are here.