August 9,1894. 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
131 
ever, excepting specially first early sorts, people will grow varieties that 
suffer severely from disease in bad seasons that is their look out. 
I base my statement that the disease has now for us no terror, on the 
fact that for several years, even when disease has been prevalent, 
Potatoes have been so cheap and abundant that it has been difficult to 
sell at remuneiative prices. When last spring old Potatoes were a drug, 
the prices went up at a bound directly it was known how seriously the 
early breadths had suffered from frost. That was, however, an accident 
of the season that will hardly be repeated in a hurry. All the same, 
of the disease has doubtless created a scare that the application of the 
mixture might have at once delayed. As to the Potato disease attacking 
Onions that is their illusion. The two things are absolutely dissimilar, 
yet both amenable to the action of sulphate of copper.—A. D. 
POTATO DISEASE (PHYTOPHTHORA INFESTANS). 
The fungus which causes this Potato disease belongs to the family 
designated Peronosporem, and is recognised specifically as Phytophthora 
Fig. 20.—lilac souvenir DE LOUIS SPATE. 
growers will risk a repetition by planting early as usual, just as some 
others will prefer to plant well-known disease-takers in bad seasons 
rather than disease-resisters. But even in their case the disease still 
should have no terrors when a couple or three dressings of the Bordeaux 
mixture can so speedily ameliorate the evil. After all, and with a 
knowledge that on particularly soft-fieshed varieties the disease in such 
a season may be very harmful, and with the further knowledge of the 
great value of Bordeaux mixture dressings, how many are there who 
are employing this simple remedy 1 Shall I say how few ? 
Mr. Orchard’s description of the way the fungus has spread in the 
island is distressing to read in face of the fact that here of all places 
was a splendid opportunity to test the Bordeaux mixture. The spread 
infestans. It attacks the Potato plants by means of conidia, or micro¬ 
scopic spores, conveyed either by the wind, by insects, dogs, rabbits, 
hares, foxes, and by human beings, or by means of spores from the 
mycelia or vegetative centres, generated within the growing plants, and 
coming from infected tubers. In very dry summers, like that of 1893, 
there is, as a rule, but little disease. On the other hand, it has been 
observed that the fungus has made rapid progress in a night temperature 
of 47° to 50° Fahr., and a day temperature ranging between 57° and 59« 
Fahr. Generally speaking, it may be said that the Potato disease is 
generated, and causes more or less serious injury in warm, showery 
weather, especially after electrical disturbances, and makes its appear¬ 
ance between the 25th of June and the beginning of August. 
