56 BULLETIISr 395, V. S. DEPARTMENT OF AGEICULTURE. 



VARIATION OF SCHEDUbE FOR LATE VARIETIES. 



Scott and Quaintaiice (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 five 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), Cfinton 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 subacetate, potassimn 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), Clmton 

 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 appfied, will 

 control peach scab as efficiently as will self-boiled lime-sulphur and 



