26 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ January 11, 1892. 
in the spots the cells are traversed by roycelium. The roots 
a'so are diseased, and the tubers produced by plants affected 
with either form of curl are ^l^vays diseased, producing growths 
that are diseased from their first appearance. This fungus has 
received the name of VerticilUu n atro album, and is believed to 
be an imperfectly develupe J condition of some Pyrenomycetous 
fungus of the genus Nectria 
Curl, however, must not be confounded with dry rot and wet 
rot fungi, which R inke and Berthold founi on decaying 
Potatoes, and are intimately connected. Reinke and Berthold 
attribute dry rot to Pusisporium Solani, Nectria Solani, Verti- 
cillium cinnibirinum, < hsetomium bortrachodes, and C. crispa- 
tum, and wet rot to Bacterium nav cula and Bacillus amylo- 
bacter. These fungi and minute organisms are inseparable from 
rotting Potatoes, or those weakened by infestation of Potato rot 
fungus, Phytophthora infestans. 
Though Curl fungus, Verticidium atro-album, must be dis¬ 
connected with Potato rot, dry and wet rot, in accordance with 
the present acceptation of tho’e terms, it appeirs to have been 
the “ dry rot,” which, towards the close of the eighteenth 
century, excited considerable alarm in Scotland and the 
northern parts of England, where it has prevailed more or less 
during the last four decades, and especially in 1873. Potato 
rot was not altogether unknown in the last century, for John 
Abercrombie, writing in 1788, states, “These (Potato) roots 
after being housed should be from time to time looked over, and 
all such as have any tendency to rottenness should be taken out, 
for such would infest those that are sound, and the infection 
would soon spread,” This may or may not have any connection 
with the Potato disease of the nineteenth century, but the advice 
is to the poin^ and its non-observance has much to do with the 
prevalence of the Potato disease at the present time, as we shall 
presently show. But we desire to refer to another fungus, 
described by Mr. W. Gr. Smith in “ Diseases of Field and Garden 
Crops” (pp. 15-29) -namely, Peziza postuma, which kills Potato 
plants, withering and drying up the leaves. This fungus pro¬ 
duces sclero la (repi’oductive bodies), passing the winter 
unchanged, but growing the following summer from those lying 
on or under the soil one to three Pezizse, bearing numerous asci, 
each ascis conta ning eight smooth oval spores, which are 
“ shot” into the air if at all dry, and th«se falling on fertile soil 
—a P tato leaf or stem only need “a soft glow of moisture ”— 
the tiniest dew drop sufficing—to promote germination and the 
reproduction of the fungus 
These fungi—Curl and Peziza—act independently of Potato 
disease, dry and wet rot, the last two resulting of attacks by 
Phytophthora, or an impaired condition of the tuber tissues 
resulting of unfavouring climatic or cultural agencies. Dry rot 
and wet rot fungi consume the starch of the Potato, therefore it 
is recommended to expose the tubers to air and heat, either that 
of the sun or artificial to check decay, drying the substance and 
saving the starch. That does not render the tubers useable 
except for manfacture into pork or for conversion into dextrine, 
and the latter processes piactically annihilate the dry rot and 
wet rot fungi. 
No cure is known for curl fungus, but it may be prevented 
by selecting sound tubers only for seed, and avoiding those 
from plants which have been worked “within an inch of their 
lives” to get up stock. All diseised plants should be pulled 
up and cleired away as soon as n diced. When the crop is dug 
all the Potato stalks should be collected into heaps and burned. 
This is equally applicable against Peziza postuma, and it is 
imperative in preventing attacks of Phytophthora infestans 
that all Potato haulms and all rubbish, including all infested 
tubers, should be collected and burned instead of leaving them 
about anywhere and everywhere to infest next year’s crop. 
The e remains the most efficient preventive step in respect 
of all Potato diseases to be taken—namely, trenching or deep 
ploughing, for fungi require light, air, moisture, warmth, and 
every essential condition of growth quite as much in their way 
as the higher plant oa which they are parasit c. and the richer 
the soil in which they grow—that is, a Potato leaf, stem, root, 
or tuber, the more luxuriant they become. Fungi like good 
“soil;’’ indeed. Potato fungi often refuse to grow in a poverty 
stricken, starved, Potato plant, because it does not afford the 
neces-iary amount of food, then converting the substance of the 
Potato into substance of its own. Fungi live on organic sub¬ 
stances, preying on other substances than their own, which 
they assimilate and inhale oxygen, and give out carbonic dioxide 
(like animals). 
These facts should be remembered and acted upon in pre¬ 
paring ground for Potatoes, never forgetting that none of the 
inorganic elements, as such, afford a favourable “ soil ” for 
Potato fungi, therefore the more of those elements that 
strengthen the Potato plant are rendered available in the soil 
for taking into its system by the roots, the less liable the plant 
so fortified will be to suffer from the attacks of parasitic fungi, 
simply because the epidermal tissues are rendered disease- 
resisting. Surface cultivation is not sufficient. It certainly 
assures abundance of organic matter, the residuum ef the 
previous crop, weeds, and manure near the surface, and that 
those on which fungi thrive, both in the soil and within the 
plant, and gives a flush to the young plant—a soft haulm, succu¬ 
lent leaves—rich in fungi food, wi^h tender epidermal t’ssues. 
These the Potato fungus is as ready to take advantage of as the 
Potato plnnt was of the rich surface soil. 
FungoA “rests” are situated on or just within the soil. 
Such only are capable of mischief to the prospective Potato 
crop. Destroy those “ rests ” and there cannot be any distri¬ 
bution of “ seed ”—no sowing, consequently no harvest of 
Potato fungus. But this must be national, conditional on every 
cultivator practising repressive measures, for one s'ovenly 
allotment suffices to infest a field, one infested field a parish, 
one labour-stirved parish a county, and that county the whole 
country. That is where the Potato fungus begins and ends. 
It comes invisibly in the spore, it departs invisibly in “fruits.” 
To destroy these “fruits ’ two expedients have been advocated, 
1, Applications of substances to the soil when vacant, as gas 
1 mo, 3 to 5 tons per acre, d'stributed evenly in autumn, left a 
few weeks, then lightly harrowed in. But the e is a difference in 
gas lime, fresh and o'd. Fresh gas lime kills everything, stale 
is little better than gypsum. Sulphite of i on, 2 cwt per acre, 
has also been recommended for destroying fungi “iruits.” 
Both applications have been found useful in some cases, whilst 
in others no benefit has accrued from the use of those substances, 
but that is no proof of the inefficiency of fresh gas lime and 
sulphate of iron 'n preventing fungoid diseases, for disinfecting 
a plot of ground or field will not sive the Potato crops grown 
in those from infection by spores scattered over them from 
neighbouring infested land or diseased crops. Disinfection 
must be genenl if the Potato crops throughout the country are 
to be disease free. 2, Burying the fungus resting spores by deep 
digging or deep ploughing, so as to prevent the spores of the 
funjus being “shot” into the air and broadcasted over the 
Potato crops. Place the Potato fungus resting spores a spit 
deep, and they are 'or ever beyond power for mischief to the 
Potato c op. True, the spores may escape by cracks in the soil, 
but the cultivator must prevent that by taking care to have a 
good tilth on the fungi-infested stratum. But recommending 
trench ng, ridging, and subsoil ploughing is simply entailing 
needless labour and expense, also impoverishing the soil by deep 
cu'tivation. it is certainly worse than useless recommending 
such procedure to hand to mouth cultivators as a panacea for 
labou'■-starved gardens and farms. Stirring the surface suits 
the means, and answers for a time better, I admit, than deep 
cultivation, particularly in soils that have been given a founda¬ 
tion by draining, trenching, or deep stirring at a previous 
period, because it saves labour, and is les< manure-exacting. 
The Journal of Horticulture states, December 24th, 1891, 
“ Side by side with the American Apples in the other portion 
of the market were bushels of English Apples, and the 
contrast was almost painful.” Neglected culture always 
produces “ trash ” and disease-stricken produce. Surface 
“ scratching ” keeps the soil full of weeds, plague-stricken 
with grubs, and a hotbed for forcing devastating fungi. Deep 
cultivation insures the greatest possible amount of assimilable 
plant food in the soil, and secures steady sustained growth 
in the plants, so essential to their health and productiveness, 
and is one of the best possible means of avoiding infesta¬ 
tions of fun^i and insects. Therefore, drain wet land ; aerate 
sweeten sour soil; ridge-expose stubborn so 1 to winter frosts. 
It is one way to avoid the Potato disease by rendering the 
plants disease-resistant, it is the way to secure the heaviest 
crops of sound Potatoes. 
Then there is the all-important question of manures. Fresh 
stable or farmyard is the worst possible, because it is not 
impossible for the spores of fungi to pa's through the digestive 
canal of animals without being ki led, and thus inhabit different 
stible or farmyard manures applied to the Potato ground. 
Fermentation in the heap destroys many forms of fungi, for 
strong heat is fatal to those and insects. This is generally 
acted upon, though some cart the manure direct from the 
manure yard and place it in the Potato rows at once, planting 
the Potatoes upon it. This, though buried, is not calculated to 
insure immunity from disease, because some “ rests ” may gain 
access to the air, and by their spores reproduce the fungus. 
The application of fresh manure in autumn is little less 
infectious, yet there is a chance of the “ resting ” spores getting 
