Forest insects can have a significant impact on the health and mortality of trees. There are different types of insects that will attack trees such as wood borers, bark beetles, defoliators, meristem feeders, and sap consumers. Most native insects are periodic pests, appearing at epidemic levels every several years causing severe harm or mortality. Other factors that increase the risk of an infestation are environmental changes and catastrophic events that damage or stress trees. Non-native invasive insects are usually more aggressive and capable of attacking healthy hosts. Alabama’s most concerning native insects are southern bark beetles. Bark beetles in large numbers will generally appear at the end of a population cycle or after a climatic adverse event attacking pines and causing noticeable mortality.
Forest diseases are not as revealing as forest insects but can be just as destructive to trees. Wood decaying fungi, viruses, bacteria, and other pathogens can invade trees and have a negative effect on health and vigor. Most native forest diseases infect trees that are stressed or damaged from an adverse condition like a drought, storm or wound. Human and animal activities such as mechanical injury or bark scraping of trees also make them susceptible to diseases. Non-native invasive pathogens can infect healthy trees and spread aggressively through host species causing significant destruction to the forest landscape. Severe infections from a pathogen can cause tree mortality.
The links below will take you to a page dedicated to an individual insect or disease.