I first saw pear rust in my orchard in Nottinghamshire three years ago on the leaves of a Doyenné du Comice tree, and it is rapidly spreading . My scab spray programme has controlled it, but I only spray those trees sensitive to scab. Beurré Bedford is scab resistant, but has proved to be prone to pear rust. I pick the affected leaves off, but this year found it on the fruit. I have never seen or heard of pear rust attacking the fruit, but in early October I found my fingers covered in brown dust after picking up a partly obscured fruit from a box of pears. On closer examination I could see several tubular growths clustered together like miniature chimneys, covered in the brown dust of fungal spores.
Has anyone else found pear rust on their fruit and how widespread is pear rust in England?
Adrian Baggaley
Pear rust on Beurré Bedford fruit
I first came across it on a client’s leaves, in Wimbledon, a few years ago, before the fruit had developed much.
After consulting RHS’s pathologist, I picked off and disposed of all the leaves with the tell-tale orange blotch.
A summary of info about its ecology, etc can be found within the RHS website:-www.rhs.org.uk > advice; scroll & > archive… > Fruit, veg…
(ie 1st item); scroll to fruit diseases, & > pear rust.
I first saw pear rust during a tour of Belgian orchards in 1999. It was on all the pear trees, obviously endemic. Nobody worried any more, it did not appear to harm the trees in any way, although they looked revolting with the majority of leaves carrying what looked like dragon’s claws.
The next occasion came in 2001 on one of my visits to Brogdale to man the Friday Helpline. A visitor, who lived near Brogdale had come that morning, bringing a sheaf of leaves showing the typical claws. Nobody knew what the disease was, but she left the leaves there and they were handed over to me on arrival. No-one had taken her name or address so I could not trace her, but I realised that it would not be long before the disease arrived in the Pear Collection, which, of course, it soon did. The disease is also no respecter of persons as I found it later on pear tree in the walled fruit garden at Highgrove!
Last year I found a few leaves carrying the red blotch with yellow margins, the early stage of the infection on my pears. I picked them off, continuing the process as more leaves showed the infection. This year the trees were clean.
It is an interesting case of a fungus that has two hosts, in spring on pears and over-wintering on the juniper. They spread to one another by windblown spores in autumn and March respectively. The main host is ‘Juniperus sabina’, the sabin, only likely to be found growing wild, but research in Belgium has shown that some garden cultivars can also act as hosts. These are ‘J. sabina’ “Blue Danube” and “tamariscifolia”, ‘J. sinensis’ “pfizteriana” and ‘J. scopularium’ “Blue Heaven”.
The present outbreak of pear rust occurred in Southern Europe in the early 1990s and spread steadily northwards. It is thought to be due to global warming and England is now considered by the fungus to be suitable. References in ‘Diseases of Fruit and Hops’ by Wormald, written in the 1930’, show that pear rust has broken out in England occasionally much earlier, but soon died out. We must now expect that it will be with us for a long time. But please note, there are a lot more nasties in Northern Europe waiting to cross the Channel, including a really nasty copper coloured winged beetle, which lays its eggs into the bark of pear trees, the maggots spend their time unobserved inside, chewing the cambium layer until it has been encircled, when the tree dies.