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Venette said researchers plan to release Chinese wasps as an attempted biocontrol agent in the Summit area "as soon as possible," perhaps this week. The wasps were released earlier this summer in St. Anthony Park, the only previously known site of infestation in St. Paul, as well as in areas of Minneapolis. Venette said it's far too early to tell if the wasps, a natural predator of the borer in their native Asia, have made progress in stemming the spread. "This is a case where people need our research results yesterday,"Venette said. Because some trees won't show telltale signs of infestation for up to five years, identifying the scope of the problem isn't easy. Indications are that the six recently removed trees may have been infested for up to three years. St. Paul officials said the confirmations didn't indicate flaws in the city's borer fighting efforts because of the lag time between infestation and confirmation. St. Paul alone has 30,000 ash trees on public land with another 100,000 or so on private property the city doesn't control. Since at least 2009, the borer has spread in the metro area to Minneapolis, Falcon Heights and Shoreview. Outstate, it's been found in La Crescent, in the southeast corner, in two locations near Winona and in rural Houston County. St. Paul has been fighting the borer on several fronts. The city is removing and replacing about 1,000 of its ash trees each year, sometimes taking out all the trees on a block. The city has allowed homeowners willing to pay for inoculations to keep trees if they treat them on schedule. The city also is inoculating selected healthy trees in infested areas. Since the metallic green ash beetle was accidentally introduced into the United States, it has killed millions of trees in 15 states. The borer larvae kill by tunneling into ash trees, then feeding on and disrupting the flow of nutrients. They leave telltale one-eighth-inch D-shaped exit wounds in the bark and serpentine tunnels underneath it. Extensive woodpecker damage is aI so an indicator. The borers are active from May to September. Rochelle Olson * 651-925-5035 Twitter:@rochelleolson EMERALD ASH BORER IN ST. PAUL • Six trees were confirmed with infestation near Summit Avenue, approximately 3 miles from St. Paul's initial outbreak sites. • Trees don't show signs of infestation for up to five years. • There are about 130,000 ash trees in St. Paul. • Chinese wasps, a natural predator of the emerald ash borer, will be released in the area soon. Page 2 of 2