42 I'EAS AND PEA CULTURE 



grown for a number of years. As soon as the crop 

 is harvested all vines should be gathered and 

 burned. 



Powdery Mildew (Erysiphe Polygoni). — This usu- 

 ally appears late in the season, is of a superficial 

 nature, and readily detected through its whitish or 

 grayish coating. The mildew may appear on any 

 part of the plant above ground. In the mature 

 state the minute black fruiting bodies may be found 

 scattered about the mildew surface. Halsted^" 

 speaks of soil treatments with sulphur, corrosive 

 sublimate, carbonate of lime, and copper sulphate 

 for the prevention primarily of stem blight. On the 

 second crop of peas mildew was quite abundant, 

 but it did not materially injure the crop. Vines 

 sprayed with bordeaux had less mildew than others, 

 but stem blight was not materially lessened. The 

 most satisfactory treatment for mildew is probably 

 the use of bordeaux. 



Root Rot Fungus (Thiclavia Vasicola). — Paddock'^ 

 declares the pea root disease is very destructive. 

 His attention was first called to it in September, 

 1900. During the following winter, soil from in- 

 fected fields was secured and greenhouse experi- 

 ments conducted. Plants in the soil were nearly 

 always attacked by fungi on the roots and stems 

 below ground. In his opinion the fungus belongs 

 to genus Rhizoctonia. He recommends the use of 

 corrosive sublimate treatment of seed as a remedy. 



Miscellaneous Pea Fungi. — Van HalP^ speaks of 

 a disease of the pea due to attacks of fungus called 



"N. J. Exper. Sta. Rpt, 1896, p. 314. 

 " Col. Exper. Sta., Bui. 69, p. 23. 

 "E. S. R., Vol. 15. 



