Thursday 13 October 2016

Pear Rust fungus

Earlier in the year I mentioned that my "Concorde" Pear tree had been infected with Pear Rust fungus, the most obvious symptom of which is bright orange spots appearing on the upper surface of the leaves:

Well, now that the year has progressed I want to show you how this fungus has developed. We have to look at the lower surfaces of the leaves for this:

On the other side of the orange patch there is now a corresponding lump or bump - a gall, I suppose.

The gall has a number of pointed spikes sticking up out of it.

Eventually the spikes turn to what looks like flowers. I'm pretty sure they're NOT flowers, but how else can I describe them?

Spores from these "flowers" are dispersed by the wind and are harboured over Winter on Juniper trees (which, unlike pears, are evergreen). Next year the pear tree will be re-infected.

Very weird, eh?

I suppose the good news is that Pear Rust doesn't seem to affect the fruit. If you want to know more about this disease there is an article on the RHS's website about it HERE.


  1. You are lucky that this fungus does not impact on the fruit. It does seem that fruit trees are much more susceptible to disease than other types of trees. I have canker and black knot on my plum and I think my nectarine (which is only 1 year old) is also infected with canker; both of these diseases can eventually kill the trees so I'm now looking to replace them with resistant varieties, if I can find them. My fingers are crossed that my other trees remain healthy.

  2. I'm pretty sure the term for the 'flowers' will be 'sporophyte', if I'm remembering that bit of the RHS L2 course properly...

    1. Thanks, Darren. I'll add that to my gardening vocabulary! ;)


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