Medicap FE 1/2" SUPER iron systemic implants are useful in all types of trees with iron deficiency, a condition known as chlorosis. Such deficiencies are normally associated with calcareous, arid or sandy soil conditions. Trees most susceptible are oak (pin oak and white oak), black locust, eucalyptus, birch, sweet gum (liquid amber), pine, magnolia, sycamore, dogwood, podocarpus, poplar, catalpa, citrus, peach, pear, apple, avocado and silver maple. One treatment will last for 2 to 3 years. Medicaps are easily installed by tapping the implants with a hammer and bolt or dowel rod into pre-drilled 1/2" diameter holes in the lower tree trunk at 4 to 6 inch spacing. The cartridge head securely plugs the small wound made to the tree trunk and the active layer of cambium will soon grow over and close the implant site. Under normal moisture conditions, the chemical will move throughout the entire tree within 14 to 21 days for quick Greenup. 10 Medicaps will treat a 14 inch diameter tree. These 1/2" SUPER implants are for trees with a trunk diameter of 8" and larger.