Citrus is subject to a wide range of problems, from frost to root rot and fungal infection. Citrus trees are hearty, resilient plants that will often bounce back from ailments if they are given proper care and the issue causing the problem is removed. But it is not always easy to tell if a citrus tree will return to health, or if it is time to remove the tree and start again. Often the severity of the tree’s decline is the only way to tell if a citrus tree is too far gone to save.
Step back and examine the canopy of a citrus from a distance. A citrus with a thin canopy is a sign of a citrus in severe decline.
Look over the limbs and twigs of a citrus. Twigs that break easily and have a brownish, brittle texture have died. If more than a third of the citrus tree’s canopy limbs have died, the tree will not recover. Look for locations where the bark is peeling back from the limbs, which are known as cankers. Cankers are fungal infections in which fungus grows beneath the bark and forces the bark to die. Cankers typically begin in the roots and spread upward. If canker has spread as far as the tree’s limbs, the tree may be infected to the point where it will not recover.
Peel back loose bark along the trunk of the tree to look for the presence of thread-like fungus. Examine the bark for insect bores in numbers great enough to kill the tree. A large infestation of insect bores will also kill the tree.
Look at the wood beneath the tree bark. Living wood should be should be greenish white. If the wood is dead, or the trunk of the tree is hollow, the tree will not survive.
Dig back the soil around the trunk of the tree and examine the roots for fungal infection as well as knotty growths caused by root knot nematodes or root rot. Roots should be white and succulent. If roots are brown and brittle, the tree is in decline and may die.
Contact your county extension service to discover which pests diseases and problems are harming citrus in your area. If your citrus has symptoms that match any of the diseases mentioned, you may be required to dispose of it to prevent the spread of the disease.