Because of the complexity of these problems, professional help is recommended when trying to diagnose a plant health problem. Certain trees are susceptible to particular diseases and insect problems. What appears to be a disease may actually be caused by other problems. Sometimes the real problem is that the tree has been weakened and/or is in declining health due to a number of causes. The disease or insect is merely being taken advantage due to its weakened defenses. Overall, the health of the tree must be addressed, as infections and infestations will continue until the tree dies.