What's eating ornamental rhubarb leaves?

HELP! I have a beautiful ornamental rhubarb plant ( 5 years now ) and it is getting eaten. Every spring it starts out gorgeous ( it's in Calgary Alberta, zone 3 ) and then by summer something is skeletonizing the leaves. It is never visible in the day. I've tried going out at 2 am with a flashlight... nothing! I've tried diatomaceous earth... no luck. There are no slime trails ( so not slugs) just these huge skeletonized leaves... the whole plant! I tried bringing a leaf to the local garden centre and they just said "nothing eats rhubarb leaves". Well guess what? SOMEthing does.... anyone out there know? Many thanks

I had earwigs eating my rhubarb leaves 2 years ago. Finally got rid of them last year. Set out saucers with vegetable oil (they'll fall in and die), and I went out about 9 pm (just after dark) and sprayed the critters with insecticidal soap. Perhaps you went out too late to see them. The earwigs did not skeletonize the leaves though - they just ate them all!
Elijablue

We don't have earwigs here. I've never seen or heard of any insect attacking ornamental or regular rhubarb, but flea beetles are an insect that skeletonizes leaves... ?

Several types pf caterpillars will do this to leaves, I know what you mean about insects eating or NOT eating Rhubarb leaves, but your talking ornamental Rhubarb which has less toxin's in the leaf, ear wigs are one insect that is found in most places and I do know they are definitely around in Calgary from spring on-wards and hibernate come winter, they are about as long as your small finger, slim and recognized by the 2 pincher's VERY visible at the rear end. these insect come out from there hiding places, (cracks in fences, under heavy leaves, they are very social insects and IF you find where they go, you will find anything from 12 -30/40 all living together) the best way I know to get rid is to stick a garden cane in the soil beside the top of the plant's, take a flowerpot and fill it with straw,shredded newspaper etc, place this filled pot upside down onto the cane and in the morning, shake the paper out ready to stamp on the earwigs or dorp all into a bucket of water and drown them, be warned these move fast.

As for searching out caterpillars, these come in all shaded of green, spots, stripes, you name it, they grow exactly like the host plant the eat, they can munch there way through hundreds of leaves a season, each type of Caterpillar (would be beautiful butterfly) will stick to it's preferred food, so the ones who feed on fruit tree leaves will not eat your Cabbages etc, the best way to seek them out is to hold the leaf in your hand, gently turn it over and use 2 hands to hold the large leaf, make sure you move the plant flat, tilt it both ways as you may not be able to see the Caterpillar, but the warmth of your hand may disturb enough to make it move, they are very slow movers, don't bite, don't run, just munch, if you find any, you either use a pair of gloves and crush them or, drop into a bucket of water, I personally like to put the ones I find onto my bird feeder, quick easy and no guilt, ha, ha, ha.
There are other things to look for like leaf eating bees, they cut off bits, take this back to there nests, other insects eat /shred leaves so I've only gave the most probable things.
Good luck and happy hunting. WeeNel.

You're right that the common earwig does occur, as an introduced species, in Calgary:
http://www.insectsofalberta.com/earwig.htm

I've never even seen one, and have not heard of anyone complaining about them. They are considered in the site above to be mainly insect-eaters, and generally beneficial in the garden.

THanks for all the help. I do appreciate it. I have seen earwigs in my Calgary garden, but not near the rhubarb, pretty much just in the compost pile....but who knows! I have very carefully searched the leaves for caterpillars, even going to the extreme of laying on the ground under the plant for half an hour searching the leaves. The damage is only done at night. Are there night-only caterpillars? I check a leaf in the morning and again in the evening and there is no change. Yet the next morning at dawn the same leaf is now half gone. This summer maybe I should host a "garden mystery" party to see who can solve the riddle! : ) Earwigs or a night prowling caterpillar that crawls to the ground before dawn.... I'll try the earwig oil trap this summer. Would something like tanglefoot on the rhubarb stalks to get crafty caterpillars harm the rhubarb? I am hopeful that the poor plant will have a chance to finish the season with leaves! Again, thanks for all the help.

Frogarbor, are the leaves being eaten entirely, or they being skeletonized (tissue removed but veins and tissue paper-like structure remaining)?

Your so right about the earwigs devouring insects, what their fav insects are is greenfly, they love them BUT they also live on our leafy plants, you should see the mess they can make of a Dahlia plant, they eat the leaf AND nibble at the flower buds and when the buds open to a full bloom, the petals are gnawed off and distorted flowers are the norm, they also like buds of Roses, most plants with Daisey like flowers. they only feed at night where they have less predators out (Mainly Birds) to eat them up.
Hope you get lucky soon, best wishes WeeNel.

Hey altagardener
The leaves are skeletonized. They are actually quite beautiful, just rather useless as a photosynthetic surface.
Any ideas?
Thanks