Zinc and manganese deficiencies appear first on the older, basal leaves. Back to Top Control Iron chlorosis can be controlled when plants are supplied with available iron. The iron may be sprayed onto the chlorotic foliage, introduced into the trunk, or added to the soil. The most lasting results are obtained through treating the soil. Generally, the treatment is most effective when done by a licensed and experienced arborist with the proper tools and equipment.
Iron chelates are more effective in inducing recovery than spray applications of iron sulfate.
Add a tablespoon of a commercial spreader-sticker to the spray mix to help the spray adhere to the leaves. For treating trees, dissolve 1 pound of iron sulfate in 20 gallons of water and add 2 ounces of spreader-sticker. Several ounces of liquid household detergent can be substituted for the spreader-sticker. The foliage should be wetted uniformly until the spray begins to drip off the leaves. If applying a spray of soluble organic complex or an iron chelate, follow the manufacturer's directions on the package label carefully.