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Sid

By Sid

Hereford, United Kingdom Gb

Could someone please tell me what is happening to this rose bush? The stems directly below the blooms are damaged and blackened. It looks as though something has bitten through the stem repeatedly. I'm not sure if there may be eggs laid in the stem, as something squishes if I push my nail against it. Thanks for your ideas!



Sam_2861 Sam_2860 Sam_2858

Answers

 

It looks like rose canker to me, which is a fungus. It's not that common in the UK but if it is that then your bush will eventually die if not treated. It can affect neighbouring bushes as well.

15 Jul, 2014

 

Cut out the infected parts straight away (and burn them). Prune back to an outward facing bud. Mulch with well-rotted manure and spray with fungicide. Feed in Spring.

If the disease persists then you may have to resign yourself to digging up the rose - and don't replant roses in that area.

15 Jul, 2014

Sid
Sid
 

No, it's not rose canker - I've been looking at pictures and it's nothing like.

If you look closely, there is a series of raised bumps along the stem just below a bud. None of the rest of the plant is affected. It causes the flowers to droop over, which seems to be a symptom.

15 Jul, 2014

 

It looks as if something's got into the stem and burrowed along and laid eggs or something - I don't recognise it, Sid. Cut one stem and slice through the middle, see what you can see inside...

15 Jul, 2014

 

Following this as its interesting to see what it is? Rose stem borer? My interest is because 2 of my roses have wilt and I can see no reason?

15 Jul, 2014

 

If this was an Ash tree, I'd be suspecting Chalaria fraxinus, or Ash dieback, but obviously, its a rose. I haven't seen that sort of patterning with canker before... but I'm wondering if anything visible is inside the blackened parts

16 Jul, 2014

 

The knobbly scar is rose sawfly see http://www.rhs.org.uk/advice/profile?PID=196.

The damaged areas need cutting out and burning before the eggs hatch. And the rose needs some tlc to get it back to full health.

Use an organic pesticide if you wish - please do not use Provado or any other insecticide containing thiacloprid (really annoyed that the RHS are still advising it's use!)

16 Jul, 2014

 

Goodness just seen it on the RHS Large sawfly page. As I have never seen it I wonder how common is this in the UK?

16 Jul, 2014

 

For distribution see the map on http://www.naturespot.org.uk/species/large-rose-sawfly. Looks like it's on the march as they're asking for sightings to be reported.

16 Jul, 2014

Sid
Sid
 

Big pat on the back for Urbanite - just been looking at the RHS pictures and the damage does look very similar. Think I've missed the boat for cutting the damaged parts off before the eggs hatch - you can see some tiny catapillars in my pictures. I must say, the words "saw-like egg-laying organs" kinda sent a chill down my spine! lol

17 Jul, 2014

 

Squish the caterpillars - still worth cutting out damaged parts as they are open doors for disease.

Some of the things in the insect world wouldn't be out of place in a horror film.

17 Jul, 2014

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