Hi, AC. My sympathies! I have cane borers, as well. I believe mine are a type of wasp but I am still researching culprit possibilities here in OR. The borers were AWFUL this year! They almost killed a few smaller, younger roses. Bored right down to the bases of some canes. I don't have any answers regarding the attraction of rose varieties. However, certain roses in my garden seem to be targeted by the buggers just as in your garden. The preference seems to be connected to cane size. My HTs are prime targets as are thick canes on other established roses. Even if plants are young, if they have a couple of thick canes, they get nailed. I sealed and resealed the canes this spring, but I could see where the villains had attempted to bore through my sealant at the ends of the canes. As I said, grrrr. I hope others on the forum can offer helpful info and advice. Thank you for posting! I'll be reading. Carol

Rose stem girdler is established in my garden, moving in several years ago. I've read ours is Coraebus rubi, and it sounds like the one you're talking about.

I don't usually do pest prevention, just live with it. What I've found is that some roses are more badly affected than others. Teas with girdled canes will keep the canes for a year or two while they grow more canes, while R. hugonis canes snap right off at the girdling, and I think also Rugosas are similarly affected. Most of the once-blooming old roses of European origin seem to have some tolerance for cane girdler, but my once-gorgeous R. hugonis was never the same after its arrival. It's particularly irritating that cane girdler chooses strong young canes of a year's growth to colonize. I'm not sure that the pest is still present in the cane by the point that you see the swelling: have you checked? I've seen a worm a few times but only rarely.

This has been my experience; I hope others will answer with more information.

I have read that rugosa roses are especially susceptible, but I do not know why. I've had 3 or 4 rugosas in my garden, but only Dart's Dash has been long term resident. So far no experience, for which I am grateful.

I noticed a few spirals on a nice new cane of Geranium when I was walking the yard last night. Pooh!

Carol, Rose stem girdler and rose cane borer are two different pests; they have very different M.O.'s. One bores a hole down the center of a cut cane to use as a nursery and the other lays eggs on a cane which when hatched burrow inside the cambium layer of the cane, going round and round as they feed then eventually exiting to mate and start the cycle over again. This destruction of the living tissue of the cane causes a swelling or bump to form and it cuts off all flow upwards to the ends of the rose cane, causing it to dry up and die from the top down to the bump. Sealing the ends of your canes is the right solution for you if you have lots of problems with them. Unfortunately, it won't do anything for the cane girdlers.

Melissa, my research told me that the cane girdlers over-winter inside the cane to emerge in very early spring. Therefore, I surmised it would be helpful to remove those canes with bumps, swellings and spirals NOW before I miss my chance in spring. No, I haven't taken a knife to those affected canes at different times of the year to look for the larvae to see if they're in there or not. Some of what I pruned out is likely last year's damage that I never pursued, but there was a lot on new canes - obviously from this year and I don't think they've emerged yet.

Rosefolly, I used to think it was mostly rugosas with this problem. At my old house, Therese Bugnet got taken out every single year with canes that would break at the swollen spots. When it reached the point of it happening to every single cane, I had to let that variety go. Yet I grew other rugosas that stayed clean - and still do. I used to think that it was the type of prickles that resembled berry canes (or visa versa) but Lillian Gibson is not like that - yet she has been horribly infested (both of my plants.) Perhaps there really is no rhyme or reason to what the insect prefers and I'm just tilting at windmills?

AC: Yes. I have a different critter attacking my roses at the moment, but I've been keeping an eye out for girdlers, too. This area is home to them (Agrilus cuprescens). All the research I've done supports your prevention methods. I've read that the heat of summer is a good time to detect the infestation. The tips of the canes tend to wilt noticibly in the heat. All the university and agricultural sites I've visited suggest pruning off the swollen area as you have been, bagging the canes (burning would work, too) and then continuing each year. I know. Argh! According to Utah State University, this procedure will knock out most of the culprits in your garden over time unless there is a host site nearby. My cane borer bombardment arrived with the antique home and garden upheaval across the street where the ecosystem was wild and wooly and hosting a legion of critters for many years. But to get back to your question regarding rose cane preferences, there was a study conducted in Utah in 1964 and published in an Entomological Society journal which noted that rose stem girdlers on raspberries selected either first year or second year canes depending on the berry variety. That implies that your curiosity about texture, density, thorns etc. could potentially produce practical "rose variety preference" ID results. Utah State University Extension looks like a good place to contact. It seems to be a hot spot for rose cane girdler conversations. Good luck with the girdler prevention! In a garden, it's always something, isn't it? I not only have cane borers, I have Verticillium wilt occupying prime rose real estate in a corner of my garden and murdering my lilacs. Nothing very satisfying is wilt resistant. Junipers? Shudder. Carol

The Utah information is summarized at (last updated Oct 2015):

http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1772&context=extension_curall

I would suggest that one try enhancing the silicon content of your canes.

https://scholar.google.com/scholar?hl=en&q=silicon+plants+insects&btnG=&as_sdt=1%2C36&as_sdtp=

The following is a earlier gardenweb discussion which contains a number of links concerning silicon and plants including its effect on discouraging insects.

http://forums2.gardenweb.com/discussions/1586199/silicon-induced-resistance-against-powdery-mildew-of-roses-caused

The above link includes the following literature quote:

"The most widely accepted mechanism for the action of silicon in increasing plant resistance to insect attack is reduced digestibility and increased hardness and abrasiveness of plant tissues due to silica deposition, mainly as opaline phytoliths, in various tissues, including ... " a quote from the following full paper:

http://onlinelibrary.wiley.com/doi/10.1111/j.1461-9563.2009.00430.x/abstract?userIsAuthenticated=false&deniedAccessCustomisedMessage=

Thank you, Carol, for pointing me in a good direction with the USU Extension information. We gardeners are stubborn folk, aren't we? We could throw in the towel and say why bother, but we keep trying to grow what we want to grow. And yes, it seems it is always something!

Henry, thank you for those links; I will get into them tonight when I have more time. I appreciate the time you took to help.

Anne

I can confirm, positively, that rugosas/hybrid rugosas are extremely susceptible to cane girdler. My progression through rose gardening included a period of several years when my rose garden was comprised primarily of hybrid rugosas: Henry Hudson, Roseraie de L' Hay, Schneekoppe, Souvenir de Philemon Cochet, Sarah Van Fleet, just to name a few. Cane girdler was severe. I just cut the cane below the girdle, and could do not more. No other course of action is known to me.

I have had no hybrid rugosas for the last seven years and have had no cane girdler anywhere in my roses during this time. I have HTs, floribundas, grandifloras, shrub roses, miniatures, climbers, and Austins....all clean of girdler.

ugh I received this wonderful Austin rose from a friend only to find it has been attacked by rose Girdler. Looked like it had affected all of the rose's canes so I removed them! Maybe that was hasty but I've got over 50 roses and I've never seen this among anyones roses out here in Washington. Does anyone know if the adults can over winter in the soil? I'm wondering if I should replace all of the soil! The rose is mostly a nub but there are some young buds above the graft so I hopefully didn't cause irreversible damage I really want this rose!

Thanks Anne! I read that the larva overwinter in the canes but do you think the adults can overwinter too?

I'm no entomologist; nowhere in anything I've read does it say anything about the length of life of the adult beetle. I certainly hope that the adults are not hibernating over winter and that when references say that there is "only one generation a year" it means they lay their eggs and die!

Anne thank you for your reassurance. I just don't want to introduce any new pests into the garden.

This is an interesting conversation. I have to withdraw, after looking it up, Coraebus rubi as the cane girdler pest that infests my garden. Mine looks and acts like the cane girdler described in this thread.

I don't have Rugosas in the garden as they don't do well in my conditions. Roses with a good deal of Multiflora in them seem to be susceptible to cane girdler. This group, which includes the Multiflora ramblers and the Hybrid Musks, have shortlived canes that are susceptible to sunburn and cane girdler. Which factors influence the others I can't say, but I find I need to stay ahead on pruning with these roses, cutting out old canes at the base to encourage the growth of new ones. Hybrid Musks will deteriorate down to nothing if I don't do this.

This thread has encouraged me to begin collecting and burning swollen parts of canes after pruning them out, so, thanks to Henry Kuska especially, for the information on life cycle and control of the pest! I've been out recently working in that part of the garden where I have the bulk of my Multifloras, and it's discouraging, and motivating to attack the cane girdler. But perhaps I can discourage them. And the area and its roses do look better after cleanup, and perhaps it's not wholly desperate to think it may turn into a decent garden one day.