Sorry to hear about your poor viburnum, alyrics. It's so odd when a pest will surprise you like that. I am an organic grower and never use any kind of pesticide so that would not be the route I would go. I would try to capture one of the caterpillars and either take it to a local nursery for identification or post a photo here, so you can figure out what you have, then you can figure out what to do. If there are no more cats to be found and no foliage, I would just keep it watered well and let it go into the winter without any intervention and see what happens next spring.

YES! I'm an organic gardener also - as much as I possibly can, I thought these cats would move on and the shrub would leaf out again. I've even sat and caught cats when they hatch from the ground and start crawling up the trunk. Never saw any like these.

Most likely not caterpillars at all.

Much more likely to be viburnum leaf beetles.

We don't yet have them here. But you should be able to obtain info about them easily. Either a google search or better yet, contact your county's Extension Service office.

Here's a clickable map to help you locate that office.
http://www.csrees.usda.gov/Extension/

Here is a link that might be useful: locate your county's Extension Service office

I saw the black cats - they were about 3/4 inch long and thin tiny little things with bristly hairs

Here's info from Cornell, with a picture of the beetle larvae.

http://www.news.cornell.edu/releases/June99/IthacaBeetle.bpf.html

Lots more pictures online.. Do a search w/ google.

Here is a link that might be useful: look like small caterpillars but aren't

Jean001 - thank you. Its certainly possible thats what they were. the poor shrub really looks bad - I'm pretty sure this season it lost a number of major trunks and branches. Hard to tell now because our leaves are all about finished dropping. If it was Viburnum Beetle, they do not appear to like the V. Rhytidophylum as they are all perfectely healthy - at least so far.
Thanks again - I guess I'm going to have to wait till next spring to see whats up
A

Here's another Cornell fact sheet regarding the Viburnum beetle. The eggs for next season's batch of beetles (and their larvae) are easily seen along the stems of the newest growth of your plant. Pruning your plant this winter will go a long way in curtailing the population.

Here is a link that might be useful: Click here

Hi - I hope this thread is still alive cause the VLBs surely are! I had a serious infestation of VLB last year, my first year with viburnum at all, mostly on V. dentatum but also a little on prunifolium. I had to resort to spraying last year because I didn't realize what was happening until it was too late to do anything else. This winter I was diligent about looking for egg casings and saw many that looked like last years (on dead ends of branches), but not new ones. But I pruned off the tips of all the branches that were dead and with egg casings and I heaved a sigh of relief thinking I had managed to control them with the spray. This week I have noticed the leaves getting lacy again and I found the tiny larvae - instar #1, I assume, on the undersides of leaves. They are really small, much smaller than the larvae I found last year which must have been later in their growth. Based on Cornell's recommendations, I have been spraying with insecticidal soap. It's very tedious, turning over every leaf and getting complete coverage, but I think I've been pretty successful on the first 3 that I did today. But I was wondering what would happen if I simply denuded the shrubs - stripped off all the leaves that have larvae on them. Last year, after the spray took effect, the shrubs were able to push new leaves and ended the summer looking very nice. If I were to remove all the leaves now, would they regrow new ones? Any thoughts? Thanks.

Not a shrub expert or do I have experience with VLBs but I am an organic gardener. The only experience I do have is with roses that will sometimes get a bug infestation that affects the foliage more than I think is good. But I do expect a rose to have more issues than other plant material and that is the conditions on which I attempt to grow them. I purchase what is thought to be healthy, low maintenance roses, but if they do have issues, I have in the past, allowed them to flower with their first flush and if the foliage is a mess after that, I've cut them down to the ground to get rid of the whole mess. My thinking has been, either they would make it or they won't. And they always managed to push out new growth and look decent for the rest of the season. But - after repeatedly doing that three seasons in a row, the rose did begin to suffer and I replaced it. I don't know if Viburnums would respond the same or not. Hopefully, someone with more Viburnmum experience will respond.

Best bet in areas known to have this insect is to scout in late winter/early spring with a view towards stripping off or pruning out egg mass-laden branch tips.

I did scout and pruned off nearly all the tips of branches that had what I thought were egg masses. They may have been left over from last year - before I learned about VLB - or I may have missed a lot of eggs. In any case, I've got the larvae now. I don't want to cut back the stems, just wondering if I stripped off the leaves - where the larvae are feeding - if I would be removing the larvae and their food and allow the plant to regrow leaves. Last year, after I sprayed in the spring and killed the larvae (second instar, larger and later than now) they did re-leaf during the summer. This year they looked great until this week.