Scottish Rock Garden Club Forum

Cultivation => Cultivation Problems => Topic started by: annew on June 25, 2011, 07:00:20 PM

Title: Pests on hydrangea - ID please
Post by: annew on June 25, 2011, 07:00:20 PM
My aunt has discovered a lot of these animals on her hydrangea leaves. They look a bit like a cross between scale insects and wooly aphids. Anybody know what they are?
Title: Re: Pests on hydrangea - ID please
Post by: Ezeiza on June 25, 2011, 07:24:21 PM
Ann, they ARE mealybugs.
Title: Re: Pests on hydrangea - ID please
Post by: Giles on June 25, 2011, 07:27:26 PM
Pulvinaria hydrangeae.
Title: Re: Pests on hydrangea - ID please
Post by: Maggi Young on June 25, 2011, 07:29:41 PM
They're horrible, that's what they are! I think Giles is correct, though I did wonder about Cottony Cushion Scale insects.....Icerya purchasi

http://bugguide.net/node/view/5748 for some photos. Yuck!  
Title: Re: Pests on hydrangea - ID please
Post by: annew on June 25, 2011, 07:44:08 PM
You guys are GOOD!
http://apps.rhs.org.uk/advicesearch/profile.aspx?pid=557
Scary little beasties, aren't they? Many thanks, folks. :-*
Title: Re: Pests on hydrangea - ID please
Post by: Maggi Young on June 25, 2011, 08:23:39 PM

Scary little beasties, aren't they? Many thanks, folks. :-*

Not so little by the looks of your photo, Anne.  :o
Title: Re: Pests on hydrangea - ID please
Post by: Ezeiza on June 25, 2011, 08:27:39 PM
Maggi and Anne, too lazy to start another thread but speaking of niceties, one year ago I saw sweet violet leaves that looked as having a cordon around the edge. If you broke this cordon lots of tiny white maggots started felling. Looked like a positive horror, yet could not find any reference to them.
Title: Re: Pests on hydrangea - ID please
Post by: Maggi Young on June 25, 2011, 08:32:26 PM
That's sounds nasty, Alberto. I have no idea what that could be... but I don't think lots of tiny maggots are ever "good"  :-X
Maybe Anthony Darby or one of the other Bug Lovers will be able to suggest what these horrors might be.
Title: Re: Pests on hydrangea - ID please
Post by: Maggi Young on June 25, 2011, 08:47:33 PM
Hang on, may have come up with something....
Sweet Violet leaf gall   Dasineura odoratae
http://www.bugsandweeds.co.uk/galls%20p2.html
"Some confusion currently exists over definitive identification of gall causers within the Viola family of plants but the scientific name reflects that this is one of the Dasineura group of gall flies which infects the Viola odorata plant in the manner shown.

The small gall fly larva causes the leaf edge to curl upwards and roll over to thicken and form a protective shelter. The underside of the leaf which is normally only slightly pubescent at best, becomes very 'furry' and, considering the normal delicate leaf structure, presents a surprisingly firm refuge for the developing larva."

Sounds a  likely candidate, and there are web photos showing the sort of cordon around leaves that Alberto describes.

Title: Re: Pests on hydrangea - ID please
Post by: Ezeiza on June 25, 2011, 09:52:51 PM
That was superfast, Maggi! I do love this forum! The bad news is that the lady told me the pest originally appeared in Buzzy Lizzies she brought from a nursery. She thought the pest was killed along with the plants) only to finally find it in the violets.

Many thanks.
Title: Re: Pests on hydrangea - ID please
Post by: Maggi Young on June 25, 2011, 10:01:26 PM
There are a number of species that attack a range of plants in a similar manner... see this example on a n Urtica from a German site  http://people.zeelandnet.nl/grada/gallen/Dasineura%20dioicae.shtml
I suspect that many of these will not be species specific but opportunistic.
Title: Re: Pests on hydrangea - ID please
Post by: Lesley Cox on June 25, 2011, 11:53:23 PM
Maybe Anthony Darby or one of the other Bug Lovers will be able to suggest what these horrors might be.

You wouldn't want to spoonerize here Maggi. ;D
Title: Re: Pests on hydrangea - ID please
Post by: Ezeiza on June 26, 2011, 01:22:49 AM
In this case it is strikingly visible.With the violets I mentioned the lesions remained green and only apparent within short distance. Thanks for showing this.
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