Worcestershire Record No. 22 April 2007 p. 33


Following on from my note in Worcestershire Record No 21 I received the following note from Edward Cox dated 24th December 2006.

“I’ve two pear trees in my garden and the gall on the leaves is thick on the one tree and none on the other. It certainly is not new. I think Rosemary Winnall’s record in 2005 is not new for Worcestershire. It was so common and abundant I had not thought is worth sending in to the record office! There is also a juniper at the other side of the house. I’ll look closely in the New Year and see if there are any deformities on it. I have not noticed anything wrong with it so far”.

John Hodson drew my attention to The Fruit Grower’s Guide publish in 1924 which contains the following:

Cluster-cups.-This is caused by a fungus (Gymnosporangium sabinæ [Rœsstelia cancellata, Reb.]), depicted in the illustration, Fig. 203. Its appearance on the leaves consists of large, raised spots or patches, yellow at first, but soon becoming red, and visible on both surfaces. The peridia, situated on the lower surtace, contain minute spores, which escape when mature. These spores are the cause of the fungus (Gymnosporangium sabinæ) found on Savin (Juniperus Sabina), and the spores of the latter fungus give rise to "Rœsstelia cancellata" on Pear growths. Savin, therefore, ought not to be grown near Pear trees. All diseased Pear leaves should be removed directly they become spotted or blotched with red, and burned. This must be done before the spores are dispersed. The only preventive is to spray the trees with Bordeaux mixture as advised for Pear scab below. The spraying should be done early as a preventative where the trees have suffered in previous years.

The drawing and caption above right are adapted from The Fruit Growers Guide FIG. 203. CLUSTER CUPS ON PEAR LEAF AND STEM. Upper part: leaf and stem with enlarged peridia. Lower part: six cluster cups, four in elevation, two in section.

There is, as they say, nothing new! The abundance of this gall does seem to fluctuate greatly between year. It is worth looking for in 2007 and we should be pleased to received records. Pictures appear in Worcestershire Record 21 or in colour on our web site to remind you of its appearance.


GREEN H 2006. Pear leaf gall caused by the rust fungus Gymnosporagium sabinae. Worcestershire Record 21:page 49.
WRIGHT J &WRIGHT HJ 1924 The Fruit-grower’s Guide. Revised edition. Virtue & Co Ltd, London
WBRC Home Worcs Record Listing by Issue Worcs Record Listing by Subject