Re: leaf troubles on Buddleia
----- Original Message ----- From: "Reidfamily" <pkssreid@comcast.net> 
To: <medit-plants@ucdavis.edu>
Sent: Monday, May 26, 2008 1:20 PM
Subject: leaf troubles on Buddleia


Hello Folks:
In the early spring when I was pruning back my Buddleia davidii 'Black
Knight', I noticed that the older leaves were quite ravaged by something I
assumed to be a pest.  There were large holes all through the leaves, and a
very dark sticky sap was at the edge of some of these holes.  I wasn't sure
if the sap was from an insect or the plant itself.  I didn't see any visible
insects or frass, and I asked an entomologist at UC Davis if the damage
brought any pests immediately to mind.  It did not, BUT he works mostly with
crop plants.  So, I've perused the UC IPM site and found nothing
particularly helpful, and the pages on both physiological and fungal
shothole didn't quite seem to match the look of things on my plant, i.e.
there were not reddish brown spots on the newest leaves, and no lesions I
can find on the stems.  I took off all the damaged leaves at pruning time,
but there is quite a bit of foliage damage tonight, and I am wondering if
anyone out there has had butterfly bush troubles of the same kind.  I have
attached a link to photos on Flicker of the front and back of a leaf.  I
apologize for the quality, as I have very unsteady hands and close-ups are
tricky for me.  It gives you the idea, though.  It may be significant that
most of the damage seems to be along veins, but I am not entirely sure.
Thanks in advance!

Karrie .
There is no reason though to apologise for your photography which was very good indeed and clearly showed the form of the damage.
I really don't know what local pests you might have but just going on the form and size of the holes I would say it does not look to me look like the work of a caterpillar, nor does it resemble any sort of fungus infection as the shothole type of damage is not ever so irregular. The same argument would apply to any physiological lesion.. I think there is no doubt this is the work of some insect
What occurred to me was that it could possibly be weevil damage, if you get such pests in your area. Weevil grubs feed largely on roots, but the adults may hide in the surface soil during the daytime and climb up feed in foliage in the night. That means that one is unlikely to see them actually operating. Another possibility is that the attackers are some kind of small beetle, but I am surprised in that case you have seen no traces of their presence as they are commonly daytime feeders. You might have to keep an eye on the new growth now you know of the problem to see if they come back for another go.
It could be worth at least finding out if there are any likely weevil or beetle candidates in your area . Your entomologist friend should be able to give you this information. 

Moira

Tony & Moira Ryan,
Wainuiomata,
Central New Zealand
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