Formosan Subterranean Termite

A Technical Report from The Bartlett Tree Research Laboratories

The Formosan subterranean termite is considered to be the most aggressive and destructive species of termite in the world, causing billions of dollars in annual damage to structures and trees. Formosan termites generally cause the same type of damage as other subterranean termites. However, the rate and amount of wood consumption is often much more rapid and extensive due to colony sizes which can reach ten times that of other termite species. Formosans eat live tree tissue including both spring growth and summer growth wood. They have been known to attack more than 47 plant species, including citrus, cedar, cherry laurel, Chinese elm, sweet gum, wax myrtle, wild cherry, willow, and white oak. Termite feeding in trees can weaken tree structure and increase the risk of tree failure. Large Formosan termite swarms often seek out hardwood trees to initiate new colonies. It is likely they initially infest large hardwoods and subsequently attack housing structures. Therefore, treatment of large landscape trees is also an important component of developing a Formosan termite management plan to reduce the risk of infestation of nearby structures.