227 
Zacharewicz, Ed. Traitement de la Maladie des Pommes de Terre , 
des Tomates et des Melons , par les Sels de Cuivre. Le Progres Agri¬ 
cole et Viticole, 14 Juillet, 1889. 
The author gives in this brief note a few points of practical value in 
the treatment of potato and tomato rot, Phytophthora infestans, DBy., 
especially as testing the efficacy of the eau celeste and sulphosteatite, 
a mixture of one part of powdered copper sulphate to nine of talc, “it 
beiug well known that alternate treatments of Bordeaux mixture and 
this powder have proved generally successful.” 
For the purpose of experimentation three lots of tomato vines were 
taken. The plants of the first were grown in hot beds upon trellises 
and carefully guarded against rapid changes of temperature by raising 
and lowering the sashes. Those of the second and third lots were 
grown without any trellises in the open air, exposed to natural condi¬ 
tions. In the first set, guarded from the heavy dews, present in that 
locality in the month of June, only three sprayings with eau celeste 
given at intervals of fifteen days, preserved the plants perfectly from 
the disease. The second, exposed to ordinary climatic conditions, was 
sprayed upon May 8, and 28, and June 18, with eau celeste, and dusted 
May 20', June 8, and 26, with the mixture of copper sulphate and talc. 
By this treatment the disease, which appeared first May 26, was 
stopped and the fruits completely preserved, while a number of plants 
to one side, left unsprayed, lost by June 10, not only their leaves, but the 
greater part of their fruit. The third set, which differed from the sec¬ 
ond only in that all six sprayings, made about the same time, were with 
eau celeste, failed to give as satisfactory results, at least one-third of 
the fruits being destroyed by the rot. This difference in favor of the 
second lot the author thinks is due to the alternate use of the copper 
solution and the sulphosteatite, and draws the following conclusions 
from his experiments: That, the malady having its seat in the organs of 
the plant, all successful treatment must be preventive, consequently 
commenced before transplanting and continued at intervals of fifteen 
to twenty days, care being taken to treat in the intervals with sul¬ 
phosteatite; that it is best cot to modify the formula for eau celeste 
given by Mr. Audoynaud—1 pound of sulphate of copper in 2 gallons of 
water and 1£ pints of ammonia, diluted with 22 gallons of water when 
cool; and that the sulphosteatite should be applied at the rate of 14J 
pounds to the acre, preferably early in the morning.— David G. Fair- 
child. 
