New YorK AGRICULTURAL EXPERIMENT STATION, 147 
In 1895 and 1896 experiments were made in bearing orchards, 
In the first season’s work’? eau celeste soap, which had given 
promising results in the hands of certain fruit growers, was com- 
pared with bordeaux mixture and shown to be inferior to it. 
Hence, in the second season’s work'** only bordeaux was used. At 
the time these experiments were undertaken the efficiency of bor- 
deaux mixture for plum leaf spot had already been thoroughly 
demonstrated by experiments at various experiment stations and 
by the experience of many practical fruit growers. But the least 
number of treatments necessary and the best time for making them 
had not been determined. The Station experiments were planned 
to throw light on these points. Without going into the details of 
the experiments the conclusions reached may be stated as follows :1° 
“Tn some seasons two treatments are most economical, but under 
conditions favorable to the disease at least three should be given. 
If but two treatments be made give the first ten days after the 
blossoms fall, but not later than June 1; make the second treat- 
ment about three weeks later. The disease may be better con- 
trolled by three treatments and usually three treatments will be most 
profitable. Make the third from three to four weeks after the 
second.” 
In the summer of 1893 the Station Horticulturist made some 
interesting and important observations on plum black knot.?°° Plain 
evidence was found that the summer conidia of the black knot 
fungus are capable of reproducing the disease through infection of 
young shoots; also, that the first knots and conidia resulting from 
such infection appear in June of the following year.1*" 
Station Bulletin No. 40, Black Knot of Plum and Cherry, which 
was published in the spring of 1892, is little more than a compila- 
tion of existing knowledge of the subject. 
POTATO. 
Most of the Station’s work on potato diseases has been along 
the line of spraying to prevent blight and rot. The need of a 
remedy for these diseases must be evident to all who are familiar 
with New York potato culture. For example, on the Station farm, 
*8 Bul. 98 (1806). 
*4 Bul. 117 (1897); same in Rpt. 16:207-213. 
*5 Bul. 170:432 (1899); same in Rpt. 18:454. 
*° Plowrightia morbosa (Schw.) Sacc. 
*™ Rpt. 12:686-688 (1893). 
