PEACH SCAB AND ITS CONTEOL. 55 



treatment. Selby (1904), Scott (1909), Scott and Ayres (1910), 

 Scott and Quaintance (1911), and others showed conclusively that 

 scab may be controlled to a degree which is entirely satisfactory 

 commercially when the first fungicidal treatment is made about one 

 month after the petals fall. The results of the writer, previously 

 reported, offer further confirmation of this work. When the applica- 

 tion is delayed so long as this, sHght scab infection is to be expected, 

 but it is usually confined to scattered, inconspicuous lesions about 

 the peduncles. It appears conclusive, therefore, that the apphcation 

 of a fungicide at the time of the shedding of the calyces is not neces- 

 sary to commercially satisfactory scab control, except possibly under 

 very extreme conditions, though at times it may be of some value, 

 and is relatively inexpensive when an application of arsenate of lead 

 is made for the plum curculio at this time. 



. Treatment about one month after 'petals fall. — The results of Selby 

 (1898 and 1904), Scott (1908 and 1909), Scott and Ayres (1910), 

 Clinton and Britton (1911), Scott and Quaintance (1911), Blake and 

 Farley (1911), and others indicate the importance of the application 

 of a suitable fungicide about one month after the petals fall. The 

 results of the writer (plats 9, 10, 13, 14, 15, 17, 19, 20, 21, and 22) 

 further confirm this work, showing clearly that for midseason varie- 

 ties this is the primarily important treatment for scab. 



Treatment three to four weeJcs before the fruit is harvested. — The work 

 cited in the preceding paragraph indicates the desirabihty of a further 

 fungicidal treatment. If scab only were considered this would be 

 made about two or three weeks after the preceding application, since 

 previously reported life-history studies have shown that infections 

 which occur later than six weeks before the fruit is harvested are not 

 likely to become injurious. However, the fact that this treatment 

 must, for the sake of economy, serve also as the final spray for brown- 

 rot makes it necessary to delay it until three weeks or a month before 

 the fruit is picked. 



VARIATION OP SCHEDULE FOR EARLY VARIETIES. 



The results of Scott and Ayres (1910), Scott and Quaintaiice (1911), 

 the writer (plats 1, 2, 5, and 6), and others show that on early varie- 

 ties commercially satisfactory scab control may be effected by a single 

 thorough fungicidal treatment about one month after the petals fall 

 and that under certain circumstances the later treatment may be 

 omitted without serious loss of efficiency. In such cases the first 

 and second treatments, as recommended for midseason varieties, will 

 suffice. In cases where there is danger of serious outbreaks of brown- 

 rot, however, the omission of the third application seems unwise. In 

 such cases the three applications, as recommended for midseason 

 varieties, should be made. 



