URBAN PEST MANAGEMENT OF CARPENTER ANTS

Abstract:
In North America 20 species of Camponotus have been recorded as pest species causing either structural damage or occurring as nuisance species. Structurally damaging species are found in the subgenera: Camponotus. Tanaemyrmex, and Myrmothrix. Carpenter ants causing the most serious damage in eastern United States include C. pennsylvanicus, C. herculeanus, and C. noveboracencis while C. modoc and C. vicinus are the chief damaging species in western United States. C. abdominalis causes damage in Florida. Other species of these subgenera are nuisance pests as well as seven species of the subgenus Myrmentoma. Urban pest management is especially applicable in control of carpenter ants where a knowledge of biology and behavior is essential. Colonies of many of these species are much larger than previously documented. Collections of colonies with over 100,000 workers have been made of C. vicinus and of over 50,000 ants for C. modoc. These numbers include both the main colony and all satellite colonies. Location of the main colony as well as satellite colonies is essential for effective control. Main colonies are most often located outside the structure in living trees, dead trees, stumps, wood piles, buried wood, or wood in contact with soil. Satellite colonies are most often encountered within the structure under insulation, in wall voids, or in other hollow areas. For an established nest outside the structure, it is not uncommon to find four to eight satellite colonies in nearby structures. In natural settings, satellite colonies are usually located in wood that has less moisture than the parent colony. The most effective chemical controls for carpenter ants with the least hazards to the homeowner, environment, technician, and the structure include the application of a dust formulation in wall voids and the use of wettable powder synthetic pyrethroids as perimeter sprays. Efficacy studies of treated surfaces show synthetic pyrethroids provide over a year of protection while organophosphates have fewer than two months of residual activity