Issue 17, October 27, 2014
Emerald Ash Borer
Emerald ash borer has been found in white fringetree, Chionanthus virginicus, in the Dayton and Springfield areas of western Ohio. Part of a dead adult found in one of the trees has been positively identified by USDA personnel along with larvae from the same tree whose anatomical characters are consistent with emerald ash borer. Live larvae were found in single trees in each of four sites. Many more dead larvae were found in the trees. It was estimated that emerald ash borers had been in the trees for at least four years.
Emerald ash borer emergence holes.
White fringetree is very susceptible to drought, and this region of Ohio has had severe drought for several years. It is likely that these trees were in decline when attacked, so it is not known whether emerald ash borer attacks healthy white fringetrees. This area also has had a large emerald ash borer infestation with many dead ash trees. In this situation, adult beetles are likely to lay eggs into various hosts.
White fringetree is in the same family, Oleaceae, as ash. Several years ago after finding emerald ash borer in the U.S., researchers screened numerous plants related to ash as hosts. The most suitable host found at that time was lilac, in which emerald ash borer larvae tunneled for a short distance over a few days before dying. I do not know whether white fringetree was tested.
White fringetrees in areas containing emerald ash borer should be inspected for this insect's presence. If suspected emerald ash borers are found, contact your local Extension office or Illinois Department of Agriculture inspector for verification.
Preventative treatment is not being recommended until more is known about emerald ash borer's ability to attack healthy trees. Imidacloprid (Merit, Imicide, others), dinotefuran (Safari), and emamectin benzoate (Tree-age) recommended for emerald ash borer treatment in ash are also labeled for application to white fringetree. (Phil Nixon)
Author:
Phil Nixon