90 



VeSMONT AaSlCtJLttmAL REtOftT 



GAINS FROM USE OF BORDEAUX MIXTURE UPON LATE POTATOES. 



White Star May— ,1891 Aug. 26, Sept. 8 313 bu. 



" " May 20, 1^2 July 30, Aug. 13, 25 291 " 



May 20, 1893 Aug. i, 16, 29 338 " 



Apr. 26, 1894 J'ne 16, J'ly 17, Aug. 30 323 " 



May 20, 1893 July 25, Aug. 13, 31 389 " 



Polaris May 15, 1896 Aug. 7, 21 325 " 



June I, 1897 July 27, Aug. 17, 28 151 " 



White Star May 10, 1898 July 21, Aug. 10 238 " 



Av'ge 3 van May 18, 1899 J'ly 26, Aug. 17, Sept. 8 229 " 



Delaware May 23, 1900 Aug. 4, 23 285 " 



" May2S, 1901 July 20, Aug. 21 170 " 



" May 15, 1902 Aug. i, 20 298 " 



Green Mt. May i, 1903 Aug. 10 361 " 



Delaware May 25, 1904 Aug. i, Sept. i 327 " 



289 bu, 



Average for fourteen years 



248 bu. 



99 " 

 114 " 



251 " 

 219 " 



257 " 



80 " 



112 " 



161 " 



225 



54 

 164 



237 

 193 



68 bu. 

 60 " 

 116 " 



134" 



124 " 



134" 

 173 bu. ii6bu. 



Coupled with spraying we recommend as a result of our 

 experiments late rather than early digging where rot is feared. 

 That is to say, leave the potatoes in the ground for at least a 

 week or two after the tops are dead. Where this is done there 

 has been little loss from rot in the cellar. 



While we have shown that thorough spraying with this mix- 

 ture is a sure remedy against both fungi and insects and recom- 

 mend it unqualifiedly for all later potatoes we appreciate the ob- 

 stacles to its use. It means some extra expense for tools and ma- 

 terials and a considerable bother especially until one learns how 

 it is easiest done. Every potato grower will therefore welcome 

 the suggestion that there is promise of at least some relief from 

 the necessity for it. This depends upon securing disease-resisting 

 varieties of potatoes. The variability shown by man and the 

 domestic animals in individual or racial resistance to specific dis- 

 eases is admitted by all. Does this occur in plants? Yes, in 

 some cases at least. For example. Russet apples do not scab, 

 whereas Fameuse are especially liable to this disease ; Red Astra- 

 chans show no rust on the leaves, while another variety alongside 

 of them may have every leaf destroyed by this fungus. W. A. 

 Orton of the U. S. Department of Agriculture has recently se- 

 cured by selection a disease-resisting variety of the cow-pea and 

 similar resistance in varieties of cotton and other plants has been 

 discovered. These facts led Professor Stuart of the Vermont 

 Station to seek by breeding and selection to secure disease-re- 

 sistant potato varieties. His results up to 1904 are summarized 

 in a recent bulletin (i) which shows that some varieties, hke Rust 



(1) Vermont Exp, Sta. Bulletin 115, May, 1905. 



