viburnum leaf beetle, a native of Europe, is expected to move into
southern New England states in the near future. The beetle has been
present in New York State, Maine and Quebec, Canada for a number
of years. Both the immature and adult stages are serious defoliators
of many viburnums.
viburnum leaf beetle feeds exclusively on many different species
of viburnum, which include: Viburnum opulus (and cultivars),
V. dentatum and V. rafinesquianum. Adults have also
been found feeding and laying eggs on V. lentago, V. acerifolium,
and V. trilobu.
pest over-winters as an egg on the twigs of the host plant. Eggs
hatch in May of the following year and the young larvae begin feeding
on the host plant foliage. Larvae are usually found feeding together
in groups. Pupation occurs 8-10 weeks later and the first adults
begin to appear around the middle of July. Adults are active up
until the first frost. Mating starts in July, and the female will
chew small holes in the twigs where she lays her eggs. She then
proceeds to cover these individual eggs with excrement giving the
bark of these twigs a roughened appearance. Each female produces
up to 500 eggs. (Source: "Insects That Feed on Trees and Shrubs."
Johnson and Lyons).
the larvae (immatures) and the adults feed voraciously on the foliage
of the host plants. Heavily attacked plants will have every leaf
skeletonized by this pest. It is the only pest that causes such
injury to viburnums.
Adults are small and brown and somewhat difficult to see. The immatures
are dark in color and can be found feeding in groups on the host
need to be aware of the signs of this beetle's injury along with
knowing what the different life stages look like. One should also
monitor for the eggs on the stems of viburnums. When found, this
pest should be treated to limit its injury and spread. Physical
removal of this pest from the host plant is difficult to obtain
especially when many plants are involved. Therefore, pesticide treatments
may be necessary to manage this pest.
from the University of Massachusetts Extension Service, 2001