ALBANY, N.Y. - Almost three years since a pine-killing wasp was found in upstate New York, its first discovery in any American forest, scientists have caught others in traps from western New York to the Adirondacks.
The Sirex woodwasp, native to Europe, Asia and northern Africa, kills pines and sometimes other conifers by introducing a toxic mucus and fungus when the female lays her eggs through the bark and into the sapwood.
"Currently there are 25 infested counties,'' said Kim Chupa, a state Department of Environmental Conservation spokeswoman.
While there are no impact data yet, infestations so far appear to be in poor quality stands of trees, or in stressed trees in otherwise healthy stands, she said.
The woodwasp has also been found in two counties in Pennsylvania and parts of southern Ontario.
Traps have also been set in parts of Vermont, Ohio and Michigan, said Claude Knighten, spokesman for the U.S. Animal and Plant Health Inspection Service.
DEC research this year is expected to focus on population densities for biological control options, Chupa said.
The wasp is about 2.5 centimetres long, its body dark metallic blue or black, and the abdomen of males is black at the base and tail, with middle segments orange, according to a U.S. federal pest alert. Its antennae are black.
One turned up in September 2004 in a bark beetle trap in Oswego County. Entomologists suspect the invasive species first reached the U.S. in wooden packing material.
In a state and federal program, 1,400 traps were subsequently set around New York. So far 48 Sirex woodwasps have been caught in 37 traps, according to the DEC.
At low populations, the woodwasps select ailing trees, and the rate of spread in the U.S. is uncertain in part because of competition from native bark beetles, according to a risk analysis for APHIS.
Richard Hoebeke, a Cornell University entomologist who found the first one, had said that if it established in the United States, it would threaten pines coast-to-coast, particularly in the pine-dense southeast.
The species has also been inadvertently introduced in New Zealand, Australia, South Africa, Uruguay, Brazil and Chile, where it attacks exotic pine plantations, killing up to 80 per cent of trees, according to the 2005 alert from the U.S. Department of Agriculture.
The DEC said that in pine plantations in Australia and South America, Sirex can fly upwards of 40 kilometres a year, a "relatively slow rate of natural spread.''
One biological control method uses a parasitic worm that infects woodwasp larvae. That has been effective in the Southern Hemisphere, federal scientists said.
The DEC and state Department of Agriculture and Markets recommended protocols for the wood products industry on ways to avoid spreading woodwasps. They include not shipping untreated wood from infested areas to uninfested areas from June through October.
