History Formosan termites are rarely found north of 35°N. They have been reported in 11 states, including
Alabama,
California,
Florida,
Georgia, Hawaii, Louisiana,
Mississippi,
North Carolina, South Carolina,
Tennessee, and Texas. Their distribution is restricted to southern areas of the United States because their eggs don't hatch below about 20 °C (68 °F). More information can also be found at University of Florida Entomology.
Spread of Formosan infestation Formosan termites, since their probable landing at the Port of New Orleans around the middle of the 20th century, have become a most serious concern to pest control regulators and researchers. In the 1970's, the United States Department of Agriculture began to track the spread of Formosan infestations. Maps of counties infested by Formosans were published by the USDA in 1975, 1990, and 2001. Universities across Texas, Louisiana, Mississippi, and Florida have published updates since then. The annual expansion rate of Formosan infestation between 1990 and present varies from 5.3% in Mississippi to 8.1% in Texas. Chouvenc & Helmick 2015 find that
C. formosanus readily
hybridizes with another invasive termite in Florida,
C. gestroi.
Economic impact Historic structures in Hawaii have been threatened, such as Iolani Palace in Honolulu. It has its greatest impact in North America.
C. formosanus is the most destructive, difficult to control, and economically important species of termite in the southern United States. The Florida Department of Agriculture and Consumer Services discusses the average cost of Formosan termite damage as
"in the $10,000 range per home.......can be much higher...in some severe cases the home may have to be demolished and rebuilt." Florida Consumer Protection. Formosan termite barriers Physical barriers to Formosan termites have been developed. Most of these barriers must be installed during construction, but a few can be installed after construction. The most important application of these post construction barriers is the stone particle barrier, used to protect exposed concrete perimeters. The
International Code Council (ICC) has issued an acceptance standard called AC 380 Acceptance Criteria for Termite Physical Barrier Systems which requires five years of controlled field trials in multiple Formosan termite infested locations. These acceptance criteria are rigorous and are drawn from the criteria used by state and federal pest control regulators for termite control methods. ==References==