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What's eating the rose foliage?

Posted by Miranda Hodgson on 13 Aug 2012 at 12:35 PM

Something is eating the leaves on the roses – if left to it, stem-like leaf veins would be all that remain. Seeing the ragged foliage and looking more closely, I see around the leaf edges tiny creatures that resemble caterpillars. They are not caterpillars, though, they are rose sawfly larvae.



There are two common species of rose sawfly in the UK, Arge pagana and Arge ochropus, with A. pagana being the most common. As to how they got there, the adult fly, which looks a bit like a brown flying ant, will have laid her eggs in tiny cuts that she made in the leaf, using her saw-like ovipositor (egg-laying organ). The roses that have been affected so far are all young containerised plants - a patio rose, ‘Sweet Dream’, climbing ‘Iceberg’ and ‘Zephirine Drouhin’, as well as some small unknown plants coming on from cuttings, one of which may or may not be ‘New Dawn’.

 

 

 

 

They are all lovely young roses and I don’t want to see them damaged so, as there are plenty of wild roses in this area, I have been checking all the plants daily, removing those leaves with sawfly larvae on them and putting them in the bin. Roses that are already in the ground, which are larger and more robust, I shall leave for the birds to clean up.

 

 

 

 

Sawfly larvae are curious little things. The slightest disturbance of the plant causes them to curl their bodies so their ‘tails’ are pointing away from the leaf. I can only guess that this must be a defence mechanism designed to put off predators, maybe with a ‘Eeww, I’m not eating that’ response. Such methods don’t work very well on humans and I’ll be nipping off the leaves of the young containerised plants as soon as I see them being chewed.

 

More about sawflies: 

A general sawfly page from the BBC

Pictures and information from Bugs and Weeds

 

Comments

richardpeeej said:

Thank you for your advice on this sawfly Miranda. There  are so many pests to consider its a wonder there is anything left for us all to enjoy. I have got rid of a lot of so many leaves on the roses today that had blackspot on them. I will be on the look out for these creatures now. I love your pictures too they are very informative....  

on 14 Aug 2012 at 12:55 AM

Miranda Hodgson said:

Glad you like the pictures, Richard - funny looking little creatures, aren't they!

Same here - seeing lots of fungal problems on roses. Lots on irises too. It seems that the wet, warm weather is causing fungal and bacterial disease to thrive this year.  Some handy advice here: www.rhs.org.uk/.../Check-those-leaves

on 15 Aug 2012 at 03:52 PM

courierdude said:

completely oblivious to 15 rose plants and a rugosa hedge in my garden, i'd like to ask these little bug heads why they bothered leaving a couple of leaves uneaten at the top of one of my young amelanchiers? i thought they were catapillars too and spared them, thinking that i would prefer to see them as butterflies than corpses..next time they are going for a swim in the bird bath! /

on 23 Aug 2012 at 12:52 AM

Miranda Hodgson said:

It seems to have been a good year for sawfly, courierdude, and I've also seen them making a mess of hardy Geraniums.

If you do remove the sawfly larvae from your plants, try putting them in a little dish that they can't escape from and leaving them for the birds - warblers and titmice all love sawfly larvae. I do this with vine weevil grubs and the birds make short work of them. Robins especially will see the dish of grubs and they will all be gone in about ten minutes.

on 24 Aug 2012 at 01:16 PM

Atten…shun! | John Breakwell's blog said:

Pingback from  Atten…shun! | John Breakwell's blog

on 02 Sep 2015 at 01:05 PM