Exotic pests are nothing new. The hemlock wooly adelgid, which
has turned woods from green to brown from the Poconos to the
Great Smoky Mountains, arrived 70 years ago on a single hemlock
a Virginia landowner imported for his Japanese-style garden. But
while federal agriculture officials struggle with adelgid and
other established pests, emerging threats, like the citrus
longhorned beetle, a wood-boring native of Asia, are presenting
new headaches. So destructive is the beetle that bans on an
array of popular plants grown in Europe, including cherry trees,
rhododendrons, and even cut roses from the Netherlands, are
under consideration by federal officials, said Faith Campbell, a
senior policy representative for the conservancy. Europe is just
one part of the $500 million international plant exporting
business that has producers from Colombia to China sending more
than three billion plants to the United States each year. Such
foreign imports could be responsible for as much as 70 percent
of the most damaging n