October 



SCIENTIFIC AGRICULTURE 



61 



diseased ; but these have no doubt merely 

 escaped the disease ; no definite evidence of 

 resistance of individual plants was found. 

 Grains or grasses are not known to be 

 attacked by this Selerotinia. A crop rota- 

 tion in which sunflowers follow grain 

 crops would seem to offer hope of lessen- 

 ing the danger of the development of this 

 disease, although tests "vvill have to be 

 made as to the length of time the fungus 

 may remain active in the soil under var- 

 ious conditions. It is evident that the sun- 

 flower field should not be on or too close 

 to the plot of ground used for garden on 

 account of the danger of infection from the 

 fungus being present on A'egetables. 



Summary. 



A stem-rot of the cultivated sunflower, 

 cau.sed by a species of Selerotinia, appear- 

 ed during 1920 and 1921 in Manitoba. The 

 disease is characterized by a rotting of 

 the stem, usually at the surface of the 

 ground, and by wilting of the plants. Cer- 

 tain weeds may also be affected as well as 

 carrots, parsnips, and other plants. The 

 fungus lives over Avinter in the soil. It at- 

 tacks sunflowers when they have attained 

 considerable growth. The fungus spreads 

 rapidly in the field. It was not found to 

 be systemic in affected plants. Sunflowers 

 sliould not be replanted on fields w^hich 

 harbor the organism. 



BIBLIOGRAPHY. 



1. — Bisb}', G. R. Selerotinia disease of sun- 

 flower in Manitoba. Abs. in Phvtopath, 

 11:49, 1921. 



2. — Broderick, F. W. A new disease of 

 parsnips. Agr. Gaz., Canada, 6 : 461- 

 462, 1919. 



3. — Clinton, G. P. New or unusual plant 

 injuries and diseases found in Connec- 

 ticut, 1916-1919. Conn. Agr. Exp. Sta. 

 Bull. 222, 1920. 



4. — 'Division of Botany, Canada Dept. of 

 Agr. Exp. Farms' Branch. Survey of 

 the prevalence of common plant disea- 

 ses in the Dominion of Canada, 1920. 

 Annual Report. 1 : 19-20, 1921. 



5. — Jagger, I. C. Selerotinia minor, n. sp., 

 the cause of a decay of lettuce, celery, 

 and other crops. Jour. Agr. Res.. 20 : 

 331-334, 1920. 



6. — Lawrence, W. H. Plant diseases in- 

 duced by Selerotinia perplexa, Nov. sp.^ 

 Wash. Agr. Exp. Sta. Bull. 107 : 1-22, 

 1912. 



7.— Morris, H. E., and D. B. Swingle. An 

 important new disease of the cultivated 

 sunflower. Abs. in Phvtopath, ]1:,50, 

 1921. 



8. — Plant Disease Survey, IT. S. Dept. Agr. 

 Diseases of cereal and forage crops in 

 the T'nited States in 1920. Plant Dis- 

 ease Bull. Suppl. 1.5: 175-176, 1921. 



9. — Stewart, F. C. Notes on New York 

 plant diseases. N. Y. Geneva Bull . 463 : 

 157-188, 1919. 



EDITORIAL NOTE. 



Dr. G. R. Bisby, the author of the fore- 

 going article, has accepted a j^ear's leave 

 of absence in order to accept a position with 

 the Imperial Bureau of Plant Pathology 

 recently established at t/ie Kew Gardens, 

 London. There are over 50 appointments 

 of plant pathologists in the overseas Do- 

 minions, Colonies and Protectorates of the 

 Britislh Empire, and this Central Bureau 

 of Plant Pathology, in London, will serve 

 as a central clearing house and co-ordinat- 

 ing agency for these scattered specialists. 



CONSPICUOUS VALUE OF 

 PURE BRED STOCK. 



The value of purebred live stock, say 

 specialists in the United States Depart- 

 ment of Agriculture, is most noticeable in 

 those cases in which the capability of the 

 animals is measured most directly. Among 

 farm animals the best illustration can be 

 found in dairy cattle, though careful year- 

 ly tests of milk and butterfat production 

 are relatively recent affairs. The enorm- 

 ous differences among dairy cows w^hen 

 given the same opportunity have been 

 brought out clearly in a great number of 

 cases, and these differences are strongly 

 inherited through both the sire and the 

 dam. The average production for pure- 

 breds and grades is much above the aver- 

 age of all milk cows, which is about 4,000 

 pounds of milk and 160 pounds of butter- 

 fat annually. — Weekly News Letter, V. 8. 

 Department of Agriculture. 



