After the holes have been filled, they should be sealed with grafting wax, paraffin, or small corks. If small corks are used, remove them after one month so they do not interfere with the tree's wound sealing process. Do not use dowels, because they will injure the tree by absorbing water and expanding. One product, Medicap Fe, is a cartridge that self-seals after application. A second method uses a liquid solution of ferric ammonium citrate and is available in premeasured doses as Iron NutriBoosters.
Professional arborists can use other methods for correcting chlorosis.
Apply trunk implant and injection treatments in May and June for best results. Treatments applied later in the year often are not as effective. Read the instructions available with commercial products for more specific information about their use. Implant and injection treatments should be effective for two or more years and may be effective for up to five years before retreatment is necessary. Hence, trees should not be treated annually with a trunk application method.