No takers on this one??? Does no one have these little grubs to contend with except me? Maybe I have alien bugs on my roses. Genetic mutations unique to my roses. Never before seen by man. Hey, this could be a money maker. I could sell tickets. Roll up, roll up, come and see the nasty little burrowing grubs. Squish a few for an extra fee.

Seriously though, I found one today and squished the stem with the grub in it. It must have been a big one as the grub exploded out through the side of the stem. Sorry, I guess that is a little graphic. I'm just pulling off the ends of the wilted stems and squeezing the area where the grub is to kill it. I don't quite know what else to do. Does anyone have any suggestions??

Gilli -- I think most folks here need more information to make a diagnosis.
If you can take pix, that might help.

If not, maybe you should start by combing through Baldo Villegas' "bugs and roses" website.

Jeri

Here is a link that might be useful: Bugs & Roses -- Baldo Villegas

Hi Jeri

Thanks for the link. I had a good look but didn't see anything relating to these mysterious grubs. The growing tip just wilts and there is no sign of anything much on the outside. If you pull off the wilted end, the stem going toward the main plant is hollowed out and down inside there is a greenish looking grub. I am assuming that something is laying an egg down in the join between a leaf and the stem. The resulting larva burrow into the stem and start eating.

I don't have a camera that will do a good enough close up for a picture. There doesn't seem to be any more fresh damage that I can see. Perhaps their season has now come and gone.

Well, darn.
I wish I could help you.

If you could send Baldo an image (or even an image of the damage) he still might be able to give you a likely answer.
There's nothing like talking to a REAL entomologist, who is also a top-notch Rosarian.

Jeri

Hi Gilli, your pest could be raspberry crown borers. I had RCB in a Westerland years ago & controlled them by cutting back canes with wilted tips. Sorry I don't have a better method of control for you.

There are insects that feed in the center of succulent new stems, but I hesitate to speculate on what you have without a good picture to work from. For instance, there are fly maggots that sometimes do stuff like this (although they more commonly form stem galls and are known therefore as "gall midges").

However, I don't know whether there are gall midges that are known to feed on rose stems or not.