FUNGUS DISEASE OF SYCAMORE 9
The Wanstead Fungus Disease
of Sycamore
BY SIDNEY WALLER
[Read 27 January 1951]
The essex naturalist for 1949 contains a short paper,
under my name entitled "Preliminary Notes on a New Fungus
Disease of Sycamore". This contains the announcement of the
discovery of an unknown fungus disease on sycamore trees in
Wanstead Park. I stated that the disease had been reported to the
appropriate authorities for investigation and I promised that the
Club would be kept informed of the progress of the investigations.
Since 1948 Dr. P. H. Gregory, of Rothamsted Experimental
Station, has collaborated with me in research on the disease and
he has now kindly consented to give the Club an account of the
present state of our knowledge of the fungus.
The complete picture of its biology cannot yet be presented but
it is established that mycological literature contains no reference
to this or any similar disease of sycamore. We have to recognise
that on our doorstep, as it were, is established a virulent fungal
parasite which presents novel features to the mycologist and is
apparently a pathogen of some magnitude. Nature does not yield
up her mycological secrets easily—they generally have to be
wrested from her, and I think that both Dr. Gregory and I fully
realised the difficult position when we started operations in Wan-
stead Park in the autumn of 1948.
Our preliminary inquiries were directed to ascertaining, if
possible, how long the fungus had existed in the Park and here we
met with considerable diversity of opinion. The Forest keepers
(Wanstead Park is a part of Epping Forest) said that this disease
("sooty trees") had been noticed in the Park for years and years.
The official explanation was that its presence was solely due to the
deepening of the River Roding which took place about five years
ago. After due consideration we discarded this evidence as quite
unreliable, particularly in view of the fact that Wanstead Park has
been the hunting-ground of several well-known and distinguished
mycologists in the past. The late Miss G. Lister was familiar with
every tree and almost every blade of grass in the Park, and it is
inconceivable that she would have overlooked this conspicuous
disease had it existed in her time.