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Sunday, July 1, 2012

Damage to Clematis Flowers - Answered

Amy,

My clematis struggled for the last two years.  But finally, this year, it's turning out big purple blooms one on top of another.   In the last couple of weeks, I noticed that something is eating large chunks out of the flower petals. 

While the damage looks similar to slug damage, there are two reasons I think it might not be slugs:  (1) the clematis grow up a tall metal obelisk trellis, and all of the flowers sit on the very top, which is a long way for slugs to climb, and (2) the leaves appear untouched, with only the flowers exhibiting the damage.  Could it be earwigs?  How would I find out?

Take a look:




I searched for caterpillars and slugs on the foliage and undersides of the blooms.  Nothing.  So I don't have anything for you to identify.  Do you have any ideas what it could be?

I did notice a spider with a web across one portion of the plant (and did not photograph it because I know you hate spiders), but it didn't look like it was causing any damage to the foliage.  Anyhow, my  philosophy about spiders in the garden is that they are generally good. 

--Rachel


Answer -

Rach,

I think you're right. Without seeing the culprit, I would guess earwigs. They feed at night and move down to the soil during the day, which is why you wouldn't see them. And they seem to have a hankering for clematis flowers too.  Slugs would be eating indiscriminately, and they don't generally enjoy climbing metal. Caterpillars would probably be eating the leaves as well. If you look closely at the flowers, do you see any small (very, very small) pellets or dots of dirt? That would be frass, or caterpillar poop. If you see any webbing (that isn't from spider mites) or any pupae, then it would be caterpillars as well. The spider is definitely helping as a generalist predator, so best to leave it. (Thanks for not taking a picture, I'm light years better than I used to be, but "surprise spiders" still make me jump).

Earwigs usually aren't a problem in mature gardens, despite the scary name. They actually eat aphids and eggs of other pests, so they can sometimes benefit a garden. They like cool, moist places during the day, which is why you can find them in basements or bathrooms on occasion. They can't really hurt you with the "pinchers" on their abdomens, and they aren't really prone to crawling into ears. They eat all sorts of things: detritus, aphids, insect eggs, and mites; but they will also sometimes feed on young plants, flowers and fruits. When that happens, there are some fairly easy ways to control them.

Earwig Control:
One thing you can do is to eliminate a lot of the hiding places they use in the daytime. If you have any potted plants, logs, or anything they can hid under during the day, you might move those to a different part of the garden for a while. Clean the area around the ground if you have any leaves or ivy around the base of the plants that you can sacrifice. If you can afford to without hurting the plants, you might remove any mulch under the plants temporarily. You probably won't be able to eliminate every place they would hide, but every little bit helps. The nice thing about earwigs, though, is that they are easy to trap. Insect traps are so satisfying, when they work, because you get to see the results of your labor. People have all sorts of earwig traps they swear by. Some people think they are more attracted to beer than anything else. Others think a little fish is in order. Some people just put a rolled up newspaper or cardboard in the garden and let it get wet during watering, so that earwigs move there during the day.  I personally like oil traps. You put out a couple of cat food cans and either fill them with 1/2 inch of some kind of fish oil or vegetable oil with a dollop of bacon grease. Earwigs are highly attracted to fish oil, but you might also attract cats and other creatures. Of course, the bacon grease might attract other things too. This trap will attract them while they're feeding. In the mornings, you can empty them and refill. At the same time, you might try a trap for resting earwigs, such as the aforementioned newspaper. In the evenings, you shake the earwigs out into a pan of soapy water.

You can buy earwig bait and some sprays for earwigs, but it seems unnecessary when the home solution seems to work better. So I recommend that you try some traps. Unless, of course, you see some frass on the leaves. Then you should apply some Bt for caterpillars. :)

--Amy

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