Posted: Sept. 23, 2009

Thiensville - Department of Public Works employees will have to go to school to learn how to inoculate ash trees.

Village Manager Dianne Robertson said bids for treatment of the ash trees came in higher than anticipated, between $6,953 to $14,082, so DPW Superintendent Andy LaFond suggested buying the insecticide and equipment to treat the trees at Village Park.

LaFond said Tree-Age, the manufacturer of the insecticide, provides training in its use.

There are 77 ash trees in the river-front park, varying in size from 6 to 42 inches in diameter. The trees along the river in the park will be done first since the river is considered a conduit to spread the emerald ash borer. The invasive species bores under bark on ash trees, disrupting the flow of nutrients in the tree which eventually weakens and dies.

The ash borer has been found in Ozaukee and Milwaukee counties.

LaFond said he is also applying for a state Department of Natural Resources grant that will cover half of the cost of doing an inventory of public trees in the village. Ash trees grow quickly and are a popular street tree in area communities. In many cases they were planted to replace American elms that died as a result of Dutch elm disease, a fungus spread by beetles.

The park trees will be treated after employees are trained in the use of the insecticide. Because leaves are beginning to fall, he is not sure if the inoculations will take place this fall or early in the spring.

He plans to establish a fund in the 2010 budget for the ongoing treatment of the trees. Tree-Age recommends injections of the insecticide every other year.