Diseased Pyracantha

[Elias]

Hi All,

I have an idea of what this is but I wanted to ask other peoples opinion, before taking drastic measures, all the affected stock has been isolated.

Can anyone identify the disease?

[Jester]

Hi Elias, how long do you think these "lumps" have been on there for? Secondly have you tried cutting one off with a razor blade and then cutting one in half to see what's inside?

[Elias]

I have slice and hacked, to try to find something and there is nothing.

[Jester]

That's fair enough Elias but, how long do you think it has been there for? Do you think it developed over winter?

[Elias]

It has progressively gotten worse, so I was thinking Fire blight or a form of canker...?

[Jester]

Well as far as Fire Blight in concerned, I was under the impression that it did'nt even exist in Australia. As far as Canker goes, well I don't think so, the appearance of canker is quite different. (By the way you still have'nt told me how long you think it's been on there for).

I had a look on the net and there is a chance it may be Venturia Inaequali (Apple scab)

I extracted the following for you and highlighted what I thought was interesting in red:

Venturia inaequalis anamorphs have been described under the names Fusicladium dendriticum and Spilocaea pomi. Whether V. inaequalis is a single species or contains several cryptic species has been a matter of debate for a long time. Recent genetic studies have revealed a considerable uniformity of the species. In addition, the fungus Spilocaea pyracanthae, a parasite of Pyracantha appeared not to genetically differ from V. inaequalis, being thus a special form of the latter.
The fruiting bodies, ascocarps appear in the form of pseudothecia. They are solitary and embedded into the host plant tissue. A pseudothecium has small dark hairs around its opening, and contains pseudoparaphyses along with asci. The asci contain eight haploid ascospores. The haploid chromosome number of V. inaequalis is seven.

The infection cycle begins in the springtime, when suitable temperatures and moisture promote the release of V. inaequalis ascospores.
These spores rise into the air and land on the surface of a susceptible tree, where they germinate and form a germ tube that can directly penetrate the plant's waxy cuticle. A fungal mycelium forms between the cuticle and underlying epidermal tissue, developing asexually the conidia, that germinate on fresh areas of the host tree, which in turn produce another generation of conidial spores. This cycle of secondary infections continues throughout the summer, until the leaves and fruit fall from the tree at the onset of winter. V. inaequalis overwinters mostly as immature pseudothecia, where sexual reproduction takes place, producing a new generation of ascospores that are released the following spring. Scab lesions located on the woody tissues may also overwinter in place, but will not undergo a sexual reproduction cycle; these lesions can still produce infective conidial spores in the spring.

Hope this is of some help Elias

[Elias]

I only acquired these plants a few weeks almost for free, hence I don't know how long the scabs have been there, they all had quite a lot of healthy foliage and some some still had their pomes. When I started chopping back I began noticing the branches and trunks and it wasn't pretty.
It could be Pyracantha scab like you mentioned Spilocaea pyracanthae, I will treat it with some Baycor (Myclobutanil) and chopping back quite hard, I'll probably have to throw most away.
Fireblight has been eradicated in Australia, but as far as I remember there has been reports of it in Melbourne in the past, I googled Spilocaea pyracanthae this info came up, very handy.
http://www.rhs.org.uk/advicesearch/profile.aspx?PID=265

Thanks for help.