The New Zealand Plant Conservation Network

The largest lophomyrtus bullata in our garden, well established and big, having been planted some nine years ago, has been developing some interesting new growth - branches flattened as per the picture. Quite a few of them now evident. Is this likely to be from a bug or a virus? And would cutting off the affected bits (about half a dozen growing tips) make any difference?

Hi William - this growth is called a fastigation - and it is caused by a variety of things such as (like you suggest) a virus infection, bacterial or fungal infection, mites, or even gall midges, all disrupting the usual meristematic tissue growth. I can't say which of these is affecting your Lophomyrtus indeed I have never seen this on any species of Lophomyrtus before. I have seen it occasionally on other indigenous trees such as Quintinia, Coprosma but not the Myrtaceae. If it were me I would prune out the infected tissue, and see if you get any further development. I have no other solutions to offer beyond an academic interest as to what is causing it, and for that I don't have any immediate solutions. You could try consulting your local plant nursery (I don't know where you are based), or you could try sending images to Oratia Native Plants Nursery and asking them if they have seen this type of thing before, and how to treat it. Their email is: [email protected].

Many thanks for the reply. I can indeed send this image to Geoff Davidson at Oratia Nursery - we get all our native plants from them. A possibly related matter is that adjacent to this Lophomyrtus bullata is a Melicope ternata which had an infection, and a few years back Geoff Davidson kindly had some infected leaves analysed by Plant and Food Research in Mt Albert. He gave me a copy of the diagnosis, which unfortunately couldn't find in my files last night. We cut that melicope right back and it has since recovered very well, though some infection has reappeared (though this is evident on many of our other wharangis). However, the visual effects of that infection are nothing like the grotesque-looking fastigation on the Lophomyrtus!