Need some help with an issue with clethra alnifolia (aka sweet
pepperbush, aka summersweet). I keep the plants extremely
well-watered (they are next to a rain barrel) and they are in full
sun...thought I had found the perfect spot for them until this
Small 1/4" long black caterpillar wiping out the leaves of two new
shrubs I purchased 6 weeks ago. The caterpillars looks very similar
to the virburnum leaf beetle larvae that have decimated the highbush
cranberries around here (this is zone 5 microclimate in northwest NJ).
However, they are black instead of the whitish color of the VLB larva.
The c. alnifolia plants were fresh and vibrant when I got them from
Edge of the Woods Nursery in Allentown, PA. The caterpillars have
wiped out the new bright-green growth to the stems (similar to
virburnum leaf beetle damage) and are now attacking the older
dark-green growth. Fresh growth is sprouting, but the caterpillars
are quickly attacking and destroying it.
All I can find on google is, "this is a pest-free shrub". When I look
up "clethra alnifolia caterpillar" or "clethra alnifolia host plant"
all the sites say, "great nectar plant" but nothing about being a
host plant for caterpillars. So I really need help with a
caterpillar/pest that doesn't seem to exist!
Thanks very much,