Alien moth pests can spread surprisingly far and fast--even over the ocean. Scientists with USDA’s Agricultural Research Service have identified the travel rates of 10 foreign species of moths--from the scientific family Lepidoptera--introduced into North America. Moths are some of the most destructive pests of U.S. crops.

Aggressive species of crop-destroying moths can spread up to 113 miles a year, although most travel 15 to 28 miles a year. The European gypsy moth spreads the slowest, about 8 miles a year, probably because of its flightless females. The browntail moth and satin moth are members of the same family as the gypsy moth, but their flying females spread much faster at 26 and 28 miles per year, respectively.

The fastest-spreading species are two cutworm moths. One travels 113 miles a year and the other can fly at least 99 miles in one continuous flight (over water). It can take from 30 to 100 years for an introduced species to occupy all suitable habitat in the United States and Canada. Nearly all accidentally introduced Lepidoptera--about 123 species--are of European origin. Six of the 10 studied came into the U.S. from both the East and West coasts. Seaports, rather than airports, have been the major points of entry.

This new information on moth travel will be useful to scientists working on insect pest control strategies, especially integrated pest management efforts where growers cooperate across county and state lines.

The February issue of ARS’ Agricultural Research magazine contains an article on moth-migration research. The magazine can also be found on the World Wide Web in .pdf (Portable Document Format) files at:

http://www.ars.usda.gov/is/AR

Scientific contact: Douglas C. Ferguson, USDA-ARS Systematic Entomology Laboratory, Washington, D.C., phone (202) 382-1785, e-mail dferguso@sel.barc.usda.gov