EXPERIMENT STATION BULLETINS. 6G7 



RECOM M ENDATIONS 



For efficient control oi' liopperburn it is necessary that the spraying 

 program be started before the over-wintering adults have migrated to 

 the potato fields. 



The first application of bordeaux mixture should be made when 

 the vines are from 3 to 6 inches high, and should be followed by tlie 

 second spraying about a week later. At least three subsequent apjili- 

 cations should be made at intervals of 10 days or 2 weeks. 



Best results are obtained by using a sprayer which is capable of 

 maintaining a pressure of 200 pounds or more and which is equipped 

 with a boom so arranged that two nozzles direct the spray upward and 

 inward from each side of the row, while a third nozzle directs the spray 

 downward and covers the upper surface of the leaves. It is important 

 that the undersides of the vines be kept well covered with bordeaux 

 because it is there that the leafhoppers feed. 



Spraying potatoes with bordeaux mixture is a form of insurance in 

 which every potato grower can afford to invest. It pays annual divi- 

 dends of increased 3-ields. During wet seasons bordeaux mixture saves 

 the crop from the ravages of late blight, while in dry seasons it turns 

 the tables on hopperburn. 



The above recommendations should be supplemented by thorough 

 eradication of weeds in and surrounding the potato field in order to 

 remove sources of later infestation. 



BIBLIOGRAPHY 



1. Goff, E. S. Treatment of fungus diseases. Jour. Myc. 7 :23-25. 1891. 



2. Plant Disease Survey Crop losses from Plant Diseases in the U. S, 



in 1919. The Plant Disease Bui. Sup. 12 :319. 1920. 



3. Jones, L. R. Potato blights and fungicides. Yt. Agr. Exp. Sta. 



Bui. 4-9. 1895. 



4. Lutman, B. F. Tipburn of the potato and other plants. Vt. Agr. 



Exp. Sta. Bui. 214. 1919. 

 Plant diseases. Twenty years' spraying for potato diseases 



and the weather. Vt. Agr. Exp. Sta. Bui. 159. 1911. 

 Some studies on bordeaux mixture. Vt. Agr. Exp. Sta, 



Bui. 196. 1916. 



5. Martin, ;W. H. Influence of bordeaux mixture on the rates of 



transpiration from abscised leaves and from potted plants. Jour. 

 Agr. Res. 7:529-548. 1916. 



6. Duggar, B. M. and Cooley, J. S. The effects of surface films on the 



rate of transpiration: experiments with potted potatoes. Ann. 

 Mo. Bot. Gard. 1 :351. 1914. 



7. Ball, E. D. Discussion of the potato leafhopper. Final Report 



War Emergency Bio'ard American Plant Pathologists, 62-66, 

 December SI, 1918. 



The potato leafhopper and the hopperburn that it pro- 

 duces. Rept. Div. Ent. Wis. Dept. Agr. 77 :102. 1918. 



and Fenton, F. A. What percentage of tipburn is caused 



by the leafhopper? Jour. Econ. Ent. 13:218. 1920. 



8. Kotila, J. E. Leafhoppers and hopperburn of potato leaves. Phy- 



topathology 10:61, 62. 1920. 



