Outside of its native Japan, Popillia japonica is found in China, Russia, Portugal, Canada and the USA. Since the first detection in the United States in a nursery near Riverton, New Jersey in 1916, it has spread to many states east of the Mississippi River (except Florida), as well as parts of Wisconsin, Minnesota, Iowa, Missouri, Nebraska, Kansas, Arkansas and Oklahoma. In more recent studies, it has also been found in Texas, South Dakota, Washington, North Dakota, as well as a few spots in California, Oregon, and Nevada (although the outbreaks in California, Oregon, and Nevada have reportedly been eradicated with chemigation). Despite regulatory efforts, by 2002 it had become established in at least 30 states. Of the states in the southern region, climatological studies predict that it will establish in all states bordering the Gulf of Mexico although the beetle still remains unable to establish in Florida. Favorable climate, availability of a wide variety of host plants, and lack of important natural enemies have influenced the spread of the Japanese beetle in the United States. The expanding area of turfgrass has also provided excellent breeding ground for the beetles whose grubs continue to be the most damaging pest of turf in the northeastern U.S.