My Garden

Mexican Orange disease - what is it, and how to cure it please.

Last post 10-09-2009 10:49 AM by Pesty. 9 replies.

• 07/09/2009 06:00 PM

  redflower Location: London Joined on: 07 Sep 2009 Posts: 5

  Reply | Contact I have a Mexican Orange which has developed a disease. This consists of white insect like objects with red centres and white frill , which gather in groups, there asre also white specs under the leaves   many leaves are going yellow     and stems are going black   Can anyone identify it please and suggest a cure / cures.   I fear it is moving onto a quince and even to a virburnham.   Many thanks for any help   Redflower

• 07/09/2009 09:20 PM	In reply to
  BB Location: Hereford Joined on: 12 May 2009 Posts: 573	Reply | Contact Possibly red spider mites? http://en.wikipedia.org/wiki/Spider_mite BB

• 09/09/2009 07:44 AM	In reply to
  bogweevil Location: Joined on: 02 Mar 2004 Posts: 2,043	Reply | Contact As far as I can tell form such small pics, it is scale insect: http://www.inra.fr/hyppz/ZGLOSS/6g---088.htm Ploish them off with insecticides based on oils or better containing thiocloprid. Boggy Beware the bat-eared bogweevil

• 09/09/2009 04:24 PM	In reply to
  redflower Location: London Joined on: 07 Sep 2009 Posts: 5	Reply | Contact  Thank you for your replies. I think the pictures I uploaded were too small, so here are more showing the growths / things in better detail, and some of the black powder on the leaves

• 09/09/2009 04:48 PM

  In reply to

  hydropiper Location: Cardiff Joined on: 23 Jun 2009 Posts: 60

  Reply | Contact You have Cushion scale (Chloropulvinaria floccifera). This insect feeds on sap and is mainly found on Camellia but also attacks the foliage of other evergreen shrubs, including holly, Euonymus japonicus, Trachelospermum, Rhododendron and Choisya. It shouldn't affect Quince which is deciduous but might affect Viburnum if it's an evergreen and not a deciduous variety. The foliage becomes heavily coated over the winter months with a sooty mould that grows on the pest’s sugary excrement. For more advice and treatment see link below.  http://www.rhs.org.uk/advice/camellias/camellia_cushion_scale.asp Chris

• 09/09/2009 09:26 PM	In reply to
  redflower Location: London Joined on: 07 Sep 2009 Posts: 5	Reply | Contact  Thank you for identifying this hydropiper. I've looked up the cures, and I'll get to it asap,   Best regards   Redflower

• 10/09/2009 07:37 AM

  In reply to

  Pesty Location: Joined on: 24 Nov 2005 Posts: 94

  Reply | Contact Sorry Hydropiper thats not Cushion scale (Pulvinaria floccifera)  but Fluted scale Icerya purchasi (I guess you could have ment its other common name used in the USA - cottony cushion scale). The give away is the fluted appearance of the egg masses. This was until recently primarily a glasshouse problem in the UK – however for the past few years it has survived quite well out of doors in London – it has a wide host range, but acacia is a favourite. The pictures show the dead/dying females – the brown blobs, and the egg masses the fluted white waxy stuff. The best time to get scales is when the eggs hatch i.e. the young nymphs.  For cushion scale this would have been in July, however fluted scale breeds continuosly so there is no best time to treat, so several sprays over the year will probably be necessary. Scale insects can be a real pain to eradicate – not helped by the fact the dead ones don’t drop off the plant so you can’t always be certain you have got rid of it.  Black stuff = sooty mould a mould that grows on the honeydew excrement of sap sucking insects.     'Trying is the first step to failure' H.J.Simpson

• 10/09/2009 10:36 AM	In reply to
  hydropiper Location: Cardiff Joined on: 23 Jun 2009 Posts: 60	Reply | Contact Thankyou pesty. I see I've got confused between cushion scale and cottony cushion scale! I imagine the treatment is perhaps similar though?  Although there isn't any RHS advice on the cottony cushion scale that I can find at the moment. But just to clarify. This is cottony cushion scale: And this is plain old cushion scale:     Chris

• 10/09/2009 10:45 AM	In reply to
  miranda Location: Oxfordshire Joined on: 17 Nov 2004 Posts: 2,977	Reply | Contact Yeah, but cottony cushion scale is still Icerya purchasi and not Pulvinaria floccifera. Fascinating little things, though, aren't they.

• 10/09/2009 10:49 AM

  In reply to

  Pesty Location: Joined on: 24 Nov 2005 Posts: 94

  Reply | Contact Top pic is adult female Fluted scale with egg masses   Bottom pic are scale insect nymphs could be any species, however seeing as its the one on the RHS advisory page they must be cushion scale (presuming the RHS entomologists check all content). Cushion scale egg masses are also white and fluffy and usually have the brown blob - but do not have the fluted appearance and are usually only found on plants in spring/early summer.   'Trying is the first step to failure' H.J.Simpson