VEGETABLE AND FIELD CROPS 



267 



Commence spraying with Bordeaux when plants are 

 6 to 8 inches high and repeat at intervals of 10 to 14 days 

 throughout the season, making,Jn all, five or six apphca- 

 tions. When bugs or flea beetles are numerous, add Paris 

 green or other poison. In case the tops have bUghted, the 



Fig. 120. — Potato scab, a, natural; 6, produced by inocula- 

 tion forming monogram R. T. After Conn. Agr. Exp. Sta. 



danger of tuber infection and consequent rot is lessened 

 by delaying the harvest of the tubers until at least a week 

 or ten days after the death of the foliage.^ 



Scab {Oospora scabies Thaxt.). — Potato scab prevails 

 in Europe, Africa, New Zealand, in all parts of the United 

 States, and probably everywhere the potato is grown. 

 Though practically all American potato scab may be 

 classed as one disease, there is some evidence that there 

 is more than one form of disease which passes under this 



1 Jones, L. R., and Morse, W. J., Vt. Agr. Exp. Sta. Rpt. 16, p. 163, 

 1902-1903. 



