Rose plant growth

mrs fish · #1 (**permalink**) 10-07-2007, 05:02 PM

Is this some sort of gall, it is growing on a a rose at the joint of two stems

Tursiops2 · #2 (**permalink**) 10-07-2007, 05:06 PM

Yes, I think that's a gall, mrs fish. I think it's called "Robin's Pincushion", but that's all I know.
T2

mrs fish · #3 (**permalink**) 10-07-2007, 05:10 PM

Does that mean it is a insect that has caused it?
I know nothing about galls.

Robins pincushion suits it

Hornbeam · #4 (**permalink**) 10-07-2007, 05:19 PM

Caused by a small wasp I believe

Tursiops2 · #5 (**permalink**) 10-07-2007, 05:19 PM

[quote=mrs fish;138169]Does that mean it is a insect that has caused it?
QUOTE]

Yes. If I remember correctly, they're caused by the larvae of something (a wasp?) which burrow into the plant, stimulating it to produce a mass of tissue in defence - a bit like an oyster secreting a pearl round a grain of sand. The larvae then live off this tissue until emergence. There are many species of gall insects, particularly on oaks, each species produces it's own form of gall.

mrs fish · #6 (**permalink**) 10-07-2007, 05:30 PM

Thanks

Cotham Marble · #7 (**permalink**) 10-07-2007, 07:06 PM

Appears to be mossy rose gall, caused by a wasp Diplolepis rosea. It may be that the name Robin's Pincushion more correctly applies to the spiny rose gall which is caused by a related species Diplolepis bicolor, and which is said to be found only on wild roses. There are other rose galls that are caused by bacteria. The wasp galls should not be a problem unless they appear in multiples in which case you may want to prune some of them off to avoid the plant putting all its energy into maintaining the galls.

CM

Hobjob · #8 (**permalink**) 11-07-2007, 08:33 AM

I photographed this last week-end, and as I had visitors with me
who had not seen it beofre I culled this infor off the web for them

Robin's Pincushion or
.... the Bedegaur gall
Diplolepis rosae

This is a spectacular gall and quite commonly seen on Dog Rose hedging. Colouration can vary from green to brilliant scarlet and eventually degenerates to rusty brown. Even small, newly formed galls can be scarlet, and some old mature galls can remain green, so colouration would not appear to be linked to maturity. Perhaps the colouration is down to what part of the plant, or which cells, have been invaded.

Eventually, as autumn approaches and the host plant starts to die back, all the galls take on a rusty brown colour and those having developed on the stems and branches will remain very much in evidence (hedge trimming permitting) even after leaf fall - as evidenced by the lower image which was taken in March.

The 'causer' in this case is a gall wasp (Diplolepis rosae) which lays its eggs in either the leaves or stem of the dog rose. One gall may contain several grubs, each in an individual chamber. Subsequently, other insects may invade the gall in order to parasitise the gall wasp grubs. The gall grubs will overwinter inside the 'apparently' dead gall, to emerge next Spring.

Galls Page 1

mrs fish · #9 (**permalink**) 11-07-2007, 07:34 PM

They are fascinating things, thanks all for the info

thunder · #10 (**permalink**) 11-07-2007, 08:30 PM

Quote:

Originally Posted by Cotham Marble

Appears to be mossy rose gall, caused by a wasp Diplolepis rosea. It may be that the name Robin's Pincushion more correctly applies to the spiny rose gall which is caused by a related species Diplolepis bicolor, and which is said to be found only on wild roses.
CM

Is Diplolepis bicolor a British species? It's not mentioned in the recent (2002) key from the Field Studies Council

henrya