The team | View unanswered posts | View active topics It is currently Fri Sep 22, 2017 8:37 pm



Reply to topic  [ 5 posts ] 
 Drimys winteri is not well 
Author Message
Site Admin

Joined: Mon Oct 29, 2007 4:06 pm
Posts: 4473
Location: Islington, London UK
Post Drimys winteri is not well
I have a 2.5m Drimys winteri growing in part-sun-part-shade that ahs acquired some kind of problem, but I can't tell if it's a disease (fungal?) or a pest.

Over a period of about 10 days, the leaves have gone pale grey in patches and most of them have fallen. The leaf reverses are covered with dark brown flecks that rub off on your finger if you rub hard.

There's a resemblance to a red spider mite infestation, but there are no webs, the gritty feel to the leaf reverses is absent and there are plants nearby that are susceptible to RSM (various Brugmansias & Persicaria amplexicaule) that are unaffected.

I suppose it could be silver leaf, but there is no sign of the fruiting bodies or the dark patches on the stems (although there is some die-back) and the brown flecks on the reverse are not typical.

The internet is unanimous that D. winteri is untroubled by pests and diseases. Apparently not always. Here are some images. All realistic suggestions are welcome.


Image

Image

Image

Image

_________________
51º33'07"N x 0º07'21"W
43m (142 feet) ASL


Mon Aug 28, 2017 8:25 pm
Profile
User avatar

Joined: Tue Oct 30, 2007 10:03 pm
Posts: 1344
Location: Inland Cornwall UK
Post Re: Drimys winteri is not well
The distribution of the damage is very odd.

It almost looks like a physical damage; sun scorch, radiation frost or chemical spray, as an initial problem with a secondary fungal colonisation. Severe frost is not likely where you are though!

Drimys winteri is one of the main hosts of Phytophthora kernoviae, but it is usually unharmed itself and even if affected that causes sudden wilting of leaves, twigs or branches not discolouration.

Does any of the colour 'scape off'? Or is it 'inside' the leaf?

Chad.


Mon Aug 28, 2017 9:53 pm
Profile
Site Admin

Joined: Mon Oct 29, 2007 4:06 pm
Posts: 4473
Location: Islington, London UK
Post Re: Drimys winteri is not well
Thanks for the ideas. There have been no sprays used all season.

The problem didn't manifest itself until less than a fortnight ago and has accelerated in the past few days, so it shouldn't be delayed frost damage. This species has been hardy for me in London for over 20 years (this plant was propagated from one at my old place). However, the damaged and lost foliage is mainly in the upper parts of the shrub and diminishes the further down one looks. The lower branches are nearly unaffected so far.

The brown spots on the reverse can be rubbed off, but the silvery grey colour is as if something has consumed the chlorophyll inside the leaf. It's not superficial.

The shrub went short of water a couple of times earlier this summer and didn't flower very profusely this year, but it was growing OK a month or two ago.

I'm inclined to spray with a general fungicide and then prune back any dying stems.

_________________
51º33'07"N x 0º07'21"W
43m (142 feet) ASL


Tue Aug 29, 2017 9:08 am
Profile

Joined: Thu Apr 24, 2008 8:58 pm
Posts: 793
Location: Oxford UK
Post Re: Drimys winteri is not well
David there is a classic pic of your problem here https://jury.co.nz/2010/10/29/outdoor-c ... solutions/
I have never had any problems with my Drimys Winteri apart from My wife and Daughter chopping mine in half because it was getting too tall :roll:
Going back to your problem David have you noticed an increase in bugs/thrips? I have them in my garden but they usually attack softer leaf tissue Brugsmansia being typical.

_________________
Cold and frosty every Winter but who cares!!


Tue Aug 29, 2017 12:53 pm
Profile
Site Admin

Joined: Mon Oct 29, 2007 4:06 pm
Posts: 4473
Location: Islington, London UK
Post Re: Drimys winteri is not well
Andy Martin wrote:
David there is a classic pic of your problem here https://jury.co.nz/2010/10/29/outdoor-c ... solutions/
I have never had any problems with my Drimys Winteri apart from My wife and Daughter chopping mine in half because it was getting too tall :roll:
Going back to your problem David have you noticed an increase in bugs/thrips? I have them in my garden but they usually attack softer leaf tissue Brugmansia being typical.


The photo does look similar, but there are no visible insects on the reverses of the leaves. Also, there are two large Brugmansias within 2m of the Drimys, as well as 5 or 6 others elsewhere in the garden, and there's no sign of this problem on any of them - or any other plant. Just the Drimys.

The only invertebrates that have been present in very high numbers this year were aphids in May & June and spiders right now. I've never had thrips in the garden, to my knowledge.

_________________
51º33'07"N x 0º07'21"W
43m (142 feet) ASL


Tue Aug 29, 2017 6:28 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 5 posts ] 

Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.