124 
THE GARDENING WORLD 
October 22, 1898. 
tfATIOflAIi 
cHRYSAjiTHEmum 
SOCIETY. 
CONFERENCE ON CHRYSANTHEMUM RUST. 
A conference upon the Chrysanthemum Rust was 
held under the auspices of the National Chrysan¬ 
themum Society, in St. Stephen's Hall, The Royal 
Aquarium, Westminster, on the evening of Tuesday, 
the nth inst. Mr. T. W. Sanders took the chair at 
six o'clock, and after a brief introductory speech 
called upon Mr. P. Waterer to read his paper on 
The Practical Aspects of the Rust. 
Mr. Waterer commenced by saying that the "rust " 
was first discovered in this country in the autumn of 
last year, but that little had been heard about it 
until the present season. There were several 
diseases that attacked the Chrysanthemum, such as 
the collapse of Golden Wedding and one or two 
other varieties ; the affection of the leaves peculiar 
to Madame Carnot and its sports ; and the spotting 
and disfiguring of the leaves of many varieties by 
thrips and other insect pests. 
The “ rust ” proper was, however, entirely different 
to these. It appeared as blisters, usually on the 
lower sides of the leaves, but occasionally upon the 
upper as well. These blisters burst in about a week 
from their time of appearance, and scattered the 
spores they contained in the form of a snuff-coloured 
powder. The affected leaves turned light green in 
the spotted areas, then brown, and finally dropped. 
All varieties did not seem to possess the same pre¬ 
disposition to attack. Souvenir des Molines was 
nearly free ; so also were Edith Tabor, Matthew 
Hudson, Ella Curtis, and C. W. Richardson ; while 
Australian Gold, Mrs. G. Carpenter, Simplicity, and 
Graphic were the worst. He thought that the spores 
got into the soil used in potting and advised his 
audience to keep their ground clean from docks and 
thistles, which also were attacked by the rust, to 
give the rubbish heap a wide berth, and to syringe 
with preventives, 
He had tried all sorts of nostrums to kill the 
spores. He had dusted with soot and tobacco 
powder, steeped the foliage in neat paraffin for 
nearly a week, and had also tried some special 
mildew destroyers. All had failed to kill the spores, 
however, and in despair he had applied to the Stock 
Exchange chemist who had made him up a mixture 
strong enough to kill the Father of Evil at a hundred 
yards, and yet it didn't kill the fungus. 
Mr. Waterer had evidently found the fungus too 
strong for him, and the audience began to feel 
uneasy about the fate of their own Chrysanthemums, 
seeing how tenacious of life this terrible disease was 
said to be. 
Mr. Massee, of the Herbarium, Kew, was then 
called upon to deal with the 
Scientific Phase of the Question. 
The audience voiced in demonstrative fashion their 
appreciation of Mr. Massee’s presence among them, 
and there was no mistaking the cordiality of the 
reception accorded him as he rose with his usual 
genial smile to give them the information that he 
knows so well how to impart. Mr. Massee had no 
need of notes in the handling of his subject, and he 
had the rapt attention of his audience all the time 
that he occupied the platform. 
He commenced by sayiDg that the rust fungus 
had been abused all round, and he felt inclined to 
take up a brief for it, for it was perfectly justified in 
doing what it had done, and under the circumstances 
it could not well have done less. It was the Chrysanth¬ 
emum growers’ own fault that the rust bad attacked 
their plants. The keynote to the whole thing was 
“overcrowding.” The Chrysanthemum grower 
would probably say that if he was to make the thing 
pay he must continue to do as he had done, and it 
was difficult to answer this, although he would like 
to ask them if it would not be better to have one 
healthy plant than fifty unhealthy ones. 
There was another great fault; they had pro¬ 
gressed in every branch of horticulture except one— 
they had forgotten to study the peculiarities of the 
life-history of parasitic fungi. It was done in every 
country except Britain. It was only necessary to 
understand the general principles of the liie-history 
of fungi in order that they might be able to attack 
and break the life-cycle of the fungus at its weakest 
part. Nowadays, however, the Chrysanthemum 
grower persisted in crowding his plants together. If 
it turned out all right, well and good! If not, then 
he blamed the rust. 
Plants attacked by parasitic fungi were often 
received at Kew, and they were invariably accom¬ 
panied by the statement that " until a few days ago 
this plant was perfectly healthy,” when it was a 
matter of certainty that the plant had been ailing 
for months. 
The lecturer used the case of the " black smut of 
Oats " as an illustration of the way this class of fungus 
worked. The spores of the fungus were in the soil, 
and attacked the Oat seed whilst it was germinating. 
It had been proved that this was the only time in it’s 
life that the Oat plant could be infected by the fun¬ 
gus. Diseased from its infancy, the Oat plant had 
thus to support the parasite for six or seven months, 
until the black smut, the fruit of the fungus, 
appeared upon the Oats, and the work of the fungus, 
as far as that particular plant was concerned, being 
now completed, its last effort was to send out its 
spores to infect other plants. 
Plants were thus affected when their owner 
thought they were perfectly healthy. It was not 
necessary to know just when the plants were 
affected, however, but the condition must be antici¬ 
pated by spraying. All the spraying in the world 
would not directly kill a disease once it had got 
hold of a- plant, but " prevention was better 
than cure." The gardener looked upon the whole 
thing as a mystery. When one of his plants suc¬ 
cumbed he did not look upon that as a disease. It 
was ODly when numbers of his plants died in appar¬ 
ently the same way that he was inclined to admit 
that there might be some disease. 
The lecturer went on to say that nearly every par¬ 
asitic fungus had two kinds of spores. The Chrys¬ 
anthemum Rust (Puccinia Hieracii) was very sim¬ 
ple in its life cycle. The specific name Hieracii was 
given because the fungus was first discovered on the 
Hawk weed (Hieracium). 
The uredo or summer spores were produced dur¬ 
ing the summer months, the uredo stage of the 
fungus commencing in spring, and lasting until the 
autumn. The snuff-coloured pustules to be seen on 
the leaves of affected plants contained myriads of 
minute, round spores. These having been shed, 
were borne in various ways to the leaves of other 
plants, which they attacked by passing through the 
epidermis of the leaf and into its tissues. From 
five to six days elapsed from the entry of the uredo- 
spore into the leaf till the formation of the pustule 
or bundle of spores. The function of the uredo- 
spore was thus to extend the geographical range of 
the fungus. The overcrowding of plants by the gar¬ 
dener, and even more, the kindly syringings which he 
gave were the chief distributary means. If the 
spores of each two or three pustules were driven 
about by the syringe they were capable of infecting 
a whole batch of plants; moreover, the syringing 
placed each spore under the most favourable condi¬ 
tions for germinating, for it moistened the surface of 
each leaf, and under such conditions the uredospore 
would in two hours germinate and pierce the tissue 
of the leaf upon which it had alighted, and would 
produce mycelium, which would run through the 
inner tissues of the leaves, and in its turn bear 
other uredospores. 
In autumn, when the leaves were beginning to fade 
they underwent a chemical change, this causing a 
change in the fruit borne by the fungus, which 
became a winter or teleutospore. The teulotospores 
did not germinate at once but lay dormant through 
the winter. They fell from the plant with the leaves 
and thus left the plant quite free. The function of 
the teleutospores was thus to tide the fungus 
over the winter when there was no matrix or host 
plant to support it. In spring the teleutospore 
germinated, produced mycelium, and this bore 
uredospores, the life-cycle being thus completed. 
Chrysanthemums in glass houses were exposed to a 
greater danger than their relatives outside, for they 
bora green leaves all the year round and thus the 
uredo stage was continuous. 
With regard to methods of getting rid of the 
fungus Mr. Massee advised the destruction of all the 
leaves from the old plants, not as the gardener 
understood destruction, for he invariably crumpled 
up the leaf in his hands and threw it beneath the 
stage, thinking that he had done all that was 
necessary, when, in reality, he had only aided the 
distribution of the spores. Burning the leaves and 
old stems must, therefore, be rigorously practised. 
The houses, but not the plants, might be sprayed 
with a solution of sulphate of iron, which would kill 
all the spores. The great thing was to destroy the 
resting spores, for then the life cycle was effectually 
broken, since no perennial mycelium was formed. 
He wondered that the “ rust ” had not appeared on 
cultivated Chrysanthemums before, for it was one 
of our commonest parasites. It affected ten genera 
and thirty species of our native plants, and was, 
moreover, widely distributed in Asia, Europe, 
Australia, and America, although it was confined to 
the natural order Compositae. The reason why it 
did not monopolise the whole of the plants it 
attacked was because in the case of the wild plants 
the balance of nature had not been disturbed, as in the 
case of the Chrysanthemums. Moreover, the leaves 
of these wildings were dry much of the time, and thus 
many of the fungus spores perished. Also, there 
was no congestion, and the parasite had not the 
opportunity to run riot in the same way as it had 
done with cultivated plants. 
The Discussion. 
Following the delivery of the twodectures there was 
a brisk discussion. 
Mr. W. Wells, of Earlswood Nurseries, Redbill, 
said that he had found petroleum, applied with the 
syringe at the rate of a tablespoonful to two gallons 
of water, the most effectual fungicide. He first saw 
the " rust ” in August of last year on Pride of 
Madford, Modesto, and Georgina Pitcher. The 
plant of the last-named variety that was attacked the 
worst had, however, given him the three best flowers 
he had. He did not believe, therefore, that they 
had so much to fear from the " rust " as some would 
have them believe. 
Mr. H. J. Jones, of Ryecroft Nursery, Lewisham, 
said that he did not know how to cure the rust, for, 
like other growers in the immediate vicinity of 
London, it had not troubled him. 
Mr. Norman Davis, The Vineries, Framfield, 
thought that the greater part of the spores were 
carried from the roofs of the houses into the rain¬ 
water tanks, and thence distributed by the syringe. 
He thought also that the dry weather had been the 
chief means of aggravating the disease, as it had not 
troubled Scotland, Wales, or the moister parts of 
England. He believed that the continual crossing 
of Chrysanthemums had weakened their constitu¬ 
tions and predisposed them to disease, whilst the 
fungus itself had attacked the weaker plants first, 
and subsequently had gathered strength as it went. 
Mr. H. Cannell, of Swanley, advised burning all 
rubbish, and endorsed the opinion that the dry 
summer had aggravated the evil. 
Mr. T. Bevan, of Finchley, N., stated his belief 
that the “ rust ” had been brought over with cuttings 
and plants from France. 
Mr. Massee, in his reply, said that the distribution 
of the spores by rainwater had been the most inter¬ 
esting point raised. To state that the “ rust " came 
from France, was begging the question, for it was to 
be seen on every hand on our own wild plants. It had 
found a new host in the Chrysanthemum, however, 
for, curiously enough, the wild Chrysanthemum in 
the East was immune. He advised them to have a 
care for their Dahlias, for they also belonged to Com¬ 
positae, and it might not be long before they were 
attacked. Spraying with a solution of sulphide, not 
sulphate, of potassium, would kill all the spores. The 
one thing to remember was to get rid of the teleu¬ 
tospores, and thus start clear every year. 
Hearty votes of thanks were given to the lecturers, 
and to Mr. T. W. Sanders for presiding. 
Mr. R. Dean moved " that the thanks of the meet¬ 
ing be accorded to the directors of the Royal 
Aquarium for the use of the hall that evening.” 
This was carried. Mr. J. W. Wilkinson responded on 
behalf of the directors, saying that they had every 
pleasure in accommodating the National Chrysanthe¬ 
mum Society on that, as on every other, occasion. 
This concluded the proceedings. 
- «■» ■ - 
Attar of Geranium is often used for adulterating 
the pure or genuine Attar of Rose. The essence is 
distilled from Pelargonium capitatum, which is ex¬ 
tensively cultivated for the purpose in the South of 
France, Turkey, Algeria, and Spain. The essence is 
a fragrant oil, much used in perfumery. 
