MEDICAP® FE Systemic Tree Implants are beneficial for trees where iron deficiencies are difficult to control by foliage or soil feeding. Iron deficiencies are normally associated with calcareous, arid or sandy soil conditions. Trees most susceptible are: Pin Oak, White Oak, Black Locust, Eucalyptus, Birch, Sweet Gum, Liquid Amber, Pine, Magnolia, Dogwood, Podocarpus, Poplar, Catalpa, Citrus, Peach, Pear, Apple, Avocado, and Silver Maple. This treatment provides long-lasting control – usually 2-3 years.