"It's going to spread" into South Jersey, said certified forester Bob Williams, owner and founder of Pine Creek Forestry in Laurel Springs, Camden County. "We have ash forests down here, so it's coming.
"It would be a mistake to act like it's not," he said. "I think it's a serious problem."
Using a computer model to direct them, state officials are checking trees in Camden, Burlington, Gloucester, Salem, Mercer, and Monmouth and in counties north to determine the degree of infestation, officials said.
The New Jersey Department of Agriculture, state Department of Environmental Protection's Forestry Service, and U.S. Department of Agriculture's Animal and Plant Health Inspection Service have set out more than 300 traps in those areas. This is the fourth year traps have been set out, but amid heightened concerns. The beetle will be active for the next month or two.
"We have made application to become part of a federal quarantine, but it has not been approved as of yet," said Lynne Richmond, a spokeswoman for the Department of Agriculture. "A quarantine would limit the movement and sale of ash trees within the federal quarantine, which involves multiple states, including Pennsylvania and New York.
She said it also would place some requirements on wood recyclers, who turn wood into wood chips and mulch, adding, "But we expect very minimal impacts on those businesses."
The emerald ash borer was first seen in the United States in Michigan in 2002 and has since spread. It is now in 23 states and two Canadian provinces.
"We have been rigorously monitoring the [emerald ash borer's] movements and educating the public about what to look for in case the beetle entered our state," New Jersey Secretary of Agriculture Douglas H. Fisher said in a statement. "Now, we will be informing homeowners about the actions they can take to protect their ash trees from this tree-killing insect."
The adult emerald ash borer is metallic green, about a half-inch long, and one-eighth inch wide, officials said. Females lay eggs on the bark of ash trees. The eggs hatch and the larvae bore through the bark to the fluid-conducting vessels underneath.
As the insects feed and develop, they cut off nutrients, eventually killing the tree, usually over three to five years.
"We've gotten a lot of calls from homeowners who say they have" the beetle, Richmond said. "But we haven't confirmed" its presence beyond the original Bridgewater location.
"If we find beetles in a trap, then we would investigate that area," she said.
Specimens, including larvae, are sent to the U.S. Department of Agriculture's Systematic Entomology Laboratory, where they can be identified.
"Since the emerald ash borer has been active just over our borders for quite a number of years, we expected that it would be found in New Jersey eventually," said State Forester Lynn E. Fleming. "The DEP will work with the Department of Agriculture and other appropriate agencies to educate landowners on how to identify this invasive beetle and mitigate infestations."
Homeowners with ash trees can take steps to protect them. Treatment products are available at local retail businesses, and state-certified pesticide applicators can treat for the borer, officials said.
Signs of beetle damage include dieback of the canopy beginning at the top of the tree and progressing through the year until the tree is bare; sprouts growing from the roots and lower trunk; split bark with an S-shaped maze called a gallery; D-shaped exit holes; and more woodpecker activity, creating large holes as the birds extract ash borer larvae.
Firewood is a vehicle for movement of tree-killing forest pests, including emerald ash borers and Asian longhorned beetles, state officials said. They recommend using locally sourced firewood at home, and when traveling, burning firewood where it was bought.
The emerald ash borer, native to Asia and eastern Russia, is believed to have been brought to America unintentionally in ash wood used to stabilize crates during shipping.
"There's no better example of animals and plants spreading around the earth," Williams said. "Many people travel and buy goods, so things pass from here to there.
"The gypsy moth came from Europe, and we're living with it 100 years later," he said. "There's no reason to think we'd stop [the emerald ash borer] here."
For more information, go to www.nj.gov/dep/parksandforests/forest/community/Emerald_Ash_Borer.htm. To report signs of the beetle to the Department of Agriculture, call 609-406-6939.