August 2, 1883. J 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
89 
P RACTICAL immunity during recent years from the scourge 
that for a long time wrought such havoc amongst the most 
important of all root crops, led to the hope, somewhat widely 
«itertained, that the destructive murrain was stamped out. We 
were never sanguine on this point, and have more than once inti¬ 
mated the possibility, or rather probability, of its reappearance 
when the conditions became favourable for the growth of the 
fungus on the leaves of the plants. It is only natural and reason¬ 
able to suppose that the absence of the disease for three or four 
years must have lessened materially the number of spores of the 
Peronospora ; but no one appears to know how long the resting 
spores retain their vitality, though it is well known that when they 
germinate, and wet and warm weather prevail, the parasite 
increases with alarming rapidity and speedily ruins the crops in 
which it becomes established. 
Having a clear remembrance of the first great outbreak of the 
Potato disease in 1845 we have watched its course, its ebbing and 
flowing, with much interest ever since. Broadly speaking, it comes 
with wet seasons and increases in proportion with the continuation 
of the rain and dull weather, influenced considerably by tempera¬ 
ture ; and during h't and dry summers it is scarcely seen. The 
summer of 1845 was like that of 1888. In a large Potato-growing 
district the ground was saturated and water stood between the 
Potato rows in gardens and fields. The early part of the season 
was cold, but the temperature rose towards the end of July, 
thunderstorms were frequent, clouds heavy, and the Potato growths 
seldom dry. The fields were like a reeking swamp, and then came 
the outbreak. No one knew what it was, nor how or whence it 
came. To this day the latter part of the problem remains unsolved, 
but the microscope under the eye of keen observers revealed the 
former. We know what the disease is now, but we do not know its 
origin or the agency by which it was introduced forty-three years 
ago. Many theories have been advanced on the subject, but one has 
conflicted with the other so notoriously, and each in turn been upset 
by facts, that not one of the said theories has met with anything like 
universal acceptance. It is of little use speculating on that point; 
bait it is both interesting and serviceable to note the fluctuations of 
the visitant—its periods of activity and its terms of rest. 
In what may be termed the early history of the disease there 
were years of comparative, and occasionally of almost absolute, 
immunity from its attacks ; and these were again followed by years 
of virulency. The soundness of the crops for two or three con¬ 
secutive years led many growers to suppose the enemy was banished. 
It was thought the fungus spores could not live for more than a 
year or two ; yet when the constantly dull, wet, and murky summer 
periods came again the disease came with them, no matter how 
long it had been abs :nt. The sequel of the sudden springing into 
life of the destructive parasite that was fondly thought to have 
spent its course, was revealed by Mr. Worthington Smith’s great 
discovery of the resting spores of the fungus, which, phoenix-like, 
ever and anon would start up as if from its own ashes. After these 
were found we could feel no security ; but experience has taught 
valuable lessons, which the public was slow to learn, whereby it 
was shown to be in the power of cultivators to materially reduce 
the injury that the enemy was capable of inflicting, by raising 
barriers against its inroads. 
When the fungus first took possession of Potato plants, poisoned 
No. 423 .—Vol. XVII., Third Series. 
the sap, and ruined the tubers, it did then what it has done since 
and is doing now—attacked the soft-stemmed, thin-leaved, and 
weaker growers first, the stronger, stouter leaved, and upright 
growers alone escaping. Some popular dwarf-topped varieties that 
were much grown when the murrain first appeared were soon exter¬ 
minated, only the coarser sorts, grown chiefly for pigs, surviving. 
It is true the dwarf-growing Ash-leaf sorts remained, but that is 
because of their early ripening, the haulm dying before the fungus 
spores were prevalent; still there have been a few seasons when 
the weather was such as to call the enemy into action earlier than 
usual, and then the Ash-leaved varieties became a mass of corrup¬ 
tion, or were only saved by digging them up before they were ripe, 
or promptly pulling up the haulm the moment the first disease 
specks were seen. Many old cultivators know that is the fact, and 
they know also that as a rule the disease does not set in with per¬ 
sistency till towards the end of July or in August, and then only 
when the weather is similar to that we are now experiencing—ex¬ 
cessive wet, little or no sun and wind, and a damp, heavy, oppres¬ 
sive atmosphere. 
We have within the past few days seen large patches of fungus- 
stricken Potatoes in gardens and allotments, and more than that, 
have purchased tubers in markets half of which were more or 
less “ tainted.” Growers of early sorts finding the crops affected 
are forcing their sale. It is the old practice over again, and unmis 
takeable evidence of the presence of the murrain. One of those 
growers informed us to-day (July 30th) that his “Hebrons” 
were “ going bad,” so he had marketed them, except some rows 
he had left for seed on the chance of their escaping, but he expected 
most of them would “ go.” He was urged to take them up at 
once, but demurred on the ground that as the skins were not set the 
tubers would shrivel and be of no use for planting. That is an 
ancient fallacy exploded years ago, and on his being assured of this 
he hastened home to take up the remnant of his crop and spread the 
tubers thinly in a shed to dry, not in the sun (if any). When this 
cannot be done, pulling up the tops, if done soon enough, will save 
the crop, but cutting them off will not, because the fungus takes 
possession of the stumped back stems above ground, penetrating to 
those below, for the tubers are only underground stems called by 
another name. All early Potatoes should be examined now, and if 
they are seen to be attacked they should either be taken up at once 
or the haulm pulled and cleared away. This can be done with¬ 
out dragging up the tubers if they are grasped between the feet 
standing on the rows, and the tops drawn with a sharp jerk. 
A number of varieties of Potatoes are on trial at Chiswick. 
Calling there on Tuesday we asked Mr. Barron if they were free 
from the murrain. His reply was in the affirmative ; and he made 
the further remark that the 29th of July was the “fatal day”— 
the date on which he hid for several years first noticed the fungus. 
We had not known the date fixed before, but it is doubtless near 
i the mark. The varieties in the plot are mostly free to strong 
growers—the last to be attacked, and the most likely to escape, 
as some of them may. They were clean and healthy, and it was 
the 30th of the month. The “ fatal day ” was past; but passing 
along a border more sheltered from the wind than the open plot is, 
the fungus was plain enough feasting on the tops of some Myatt’s 
Ash-leaf. “ It struck them yesterday,” remarked the guide, “ as we 
should have seen if we had been here.” It is not unlikely. It was 
on the thin small leaves near the summit of the stems—the most 
vulnerable part; the most resisting are the robust growers, with 
strong leaf power, that can keep the sap in a pure state by elabo¬ 
ration, and the thick cuticle is also the less penetrable by the para¬ 
site. Raisers of Potatoes from seed, ripened by vigorous English 
varieties of good constitution, have done much to impart confidence 
in the safety of a crop on which so much depends ; and a more 
intelligent system of seed selection and culture that have been 
fostered by competition, may stand the country in good stead this 
year. But for the extended planting of sTong-constitutiored 
No. 2079 .—Vol. LXXIX., Old Series. 
