56 BULLETIN 395, U. S. DEPARTMENT OF AGRICULTURE. 
VARIATION OF SCHEDULE FOR LATE VARIETIES. 
Scott and Quaintance (1911) showed clearly that while the treat- 
ment recommended for midseason varieties will go far toward con- 
trolling scab on highly susceptible late varieties, the addition of an 
application of the fungicide alone four or &ve weeks after the second 
regular treatment, or about eight or nine weeks after the petals fall, 
may materially increase the efficiency of scab control and thoroughly 
justify itself economically. 
THE FUNGICIDE TO USE. 
The first and most difficult requisite of a satisfactory fungicide for 
the summer spraying of peaches is that it must not be seriously 
injurious to the host, whether applied alone or in conjunction with a 
satisfactory internal poison for insects. Furthermore, of course, the 
spray must be efficient, cheap, and reasonably easy to prepare and 
apply, and it must not leave seriously objectionable residues upon 
the fruit at harvest time. From the work of Sturgis (1901), Bain 
(1902), Scott (1907 and 1908), Lewis (1910), Clinton and Britton 
(1911 and 1912), Blake and Farley (1911), Norton and Symons (1912), 
and others, it is clear that Bordeaux mixture, soda Bordeaux, ammoni- 
acal copper carbonate, copper sub acetate, potassium sulphid, home- 
boiled lime-sulphur, and various proprietary preparations of copper, 
sulphur, and lime-sulphur, in concentrations to be economically 
efficient, have failed to meet the first of these requirements and are 
not to be recommended, save possibly under very exceptional con- 
ditions, for the summer spraying of peaches. The work of Scott 
(1907, 1908, and 1909), Scott and Ayres (1910), Lewis (1910), Clinton 
and Britton (1911 and 1912), Scott and Quaintance (1911), Blake 
and Farley (1911), Norton and Symons (1912), the writer (plats 2, 6, 
14, 15, 20, and 22), and others shows conclusively that self -boiled 
lime-sulphur, properly prepared and applied, will meet all of the 
requirements mentioned above and will satisfactorily control peach 
scab. Clinton and Britton (1912, p. 373-375) report that in their ex- 
periments a proprietary sulphur paste controlled peach scab as well 
as did self -boiled lime-sulphur, but that in certain cases when it was 
applied with arsenate of lead serious foliage injury resulted. They 
were inclined to believe, however, that this injury resulted from the 
insecticide. Blake and Farley (1911, p. 22) reported promising 
results from the use of the same sulphur paste in combating peach 
scab, but their experiments were not sufficiently extensive to justify 
conclusions. Norton and Symons (1912) sprayed peaches with this 
fungicide, but reported (p. 268) that the results obtained were too 
variable to be conclusive. The writer's results (plats 1, 2, 6, 9, 14, 
15, 20, 21, and 22) indicate that sulphur paste, properly applied, will 
control peach scab as efficiently as will self -boiled lime-sulphur and 
