For years, viburnums were an excellent choice for gardeners in many parts of the U.S. looking for an attractive, trouble-free shrub to add to their landscapes. With showy flowers, ornamental berries and nice fall color to recommend them, various species of viburnums were valuable garden standbys. Then came the viburnum leaf beetle.
Feeding by this voracious Eurasian native, which dines exclusively on viburnums, can result in the death of plants. The beetle was first found in this country in 1994 and since then has gradually expanded its range. It is now found throughout New England and most of New York State, as well as parts of New Jersey, Pennsylvania, Ohio and Michigan. A separate infestation has been found in the Pacific Northwest.
Are gardeners going to have to give up on viburnums? Not if they choose wisely. Researchers at Cornell University in Ithaca, NY have compiled a list that rates viburnum species according to their susceptibility to leaf beetle damage. While gardeners in areas where the beetle has invaded may choose to pass on susceptible species such as arrowwood and American and European cranberry bushes, there are quite a few species that show little damage. Among the least susceptible are Korean spice, Judd, doublefile, leatherleaf, tea, Siebold, dawn and David viburnums.
In an effort to help gardeners deal with the threat this beetle poses, scientists from a number of departments at Cornell University set up a website with information on the life cycle, distribution and controls of this pest, as well as the Viburnum Leaf Beetle Citizen Science Project. Participants in the project monitor their gardens, parks, or school yards throughout the spring and summer, looking for viburnum leaf beetles. They can also look for leaf beetle eggs in winter. If they find the beetle in any stage of its lifecycle, they report via an online form when and where they found the insect.
For more information on the viburnum leaf beetle and a complete list of viburnum species susceptibility ratings, go to: Viburnum Leaf Beetle.
Article published on October 5, 2010.