Avoid overfertilization since lime anthracnose thrives on luxuriant growth. Copper sprays have been used for control but are often not satisfactory because Key lime usually has new growth. Diplodia dieback can be a serious fungus problem. There may be drooping, wilting, and dieback of twigs on scattered branches, with whole branches affected eventually. For more information and control measures, consult your county agricultural extension agent.
Greasy spot can cause serious leaf loss.
Look for slight blisters like irregular flecks of grease on the undersides of leaves , with corresponding yellowed or light spots on the upper side. Future outbreaks can be prevented by timely sprays of benomyl or copper. Foot rot can attack the trunk and crown roots and seriously damage the tree. There may be some gum oozing. Affected bark eventually dries, cracks, and drops off.