Here’s HerbDoc with another nasty pest to look out for:
For gardeners like me who love their viburnums, a warning is out regarding the Viburnum Leaf Beetle, Pyrrhalta viburni. The native range of this beetle includes most of Europe, and it was first found in North America in Ontario, Canada. In 1996 it was discovered in New York State when native plantings of arrowwood (viburnum) were heavily damaged.
The beetle adults are about a quarter inch long. Their dorsal surface has small dense punctures and they look somewhat wrinkled in appearance. The larvae are also less than a half inch long and feed voraciously on leaves in May and June, skeletonizing them. In July to September leaves are heavily chewed and terminal twigs with have egg “caps” arranged in straight rows.
Heavy infestations can defoliate shrubs and cause dieback. Eventually the shrubs will be killed. According to the research this beetle prefers the popular arrowwood (V. dentatum complex), European cranberrybush viburnum (V. opulus), American cranberry bush viburnum (V. trilobum), and Rafinesque viburnum (V. rafinesquianum).
Luckily my favorite Korean spice viburnum (V. carlessi) is said to be resistant as are leatherleaf (V. rhytidiophyllum), doublefile (V. plicatum var. tormentosum), Judd (V. x juddi) and Burkwood (V. burkwoodi).
I’m keeping a very close on the native viburnums that checker my woods though. Management guidelines include pruning and destroying infested twigs after egg laying ceases in the fall (October to April). Pesticides may be effective in controlling larvae or adults; be sure the product is labeled for leaf beetles.