1>74 PLANT DISEASES 



Drop or Rot {Sderotinia libertiana). — Base of the leaves or stem 

 rots off, allowing leaves to drop. 



Control . — Sterilize the soil with steam before planting. See 

 under Ste<im in Cliapter XV, p. 253. 

 RosEiTE {lihizodonia sp.). — A rotting or daniping-off of the stem. 

 Late affected plants have a rosetted appearance. 



Control. — Start seed in steam-sterilized soil, and transfer to 

 beds that have l)een sterilized with steam, as for Drop. 

 Muskraelon. Anthracn'Ose ( Colletotrichum lagenarium) . — Dead spots 

 on the leaves and stems and sunken pits on the fruit. Thorough 

 and frequent spraying with bordeaux mixture will hold this dis- 

 ea.se in check. 

 Do w.\ Y Mildew. — The .same disease as on cucumbers (p. 270) . Often 

 very destructive. 



Control. — A satisfactory method is not known. Spraying as 

 for cucumber mildew has not proved effective. 

 Wilt. — See Cucumber. 

 Nectarine. Yellows, etc. See under Peach, p. 276. 

 Nursery Stock. — Foliage on young trees is apt to be attacked by 

 various leaf-spot fungi. The damage comes in reducing growth, 

 thus often making seconds. Several applications of bordeaux 

 mixture to keep the new growth protected are beneficial. 

 Oats. Rust {Puccinia coronata). — A red rust of the blades. 

 Control. — There is no known method of control. 

 Smut. — See under Smut of Cereals, p. 260. 

 Onion. Mildew (Peroriospora schleideniana) . — Causes a wilt or 

 blight of the leaves. 



Control. — Spray with bordeaux mixture, 5-5-50, to which has 

 been added one gallon of resin-sal-soda sticker. The first applica- 

 tion should be made when the third leaf has developed, and the 

 application should be repeated every ten days until the crop is har- 

 vested. 

 Smut ( Urocydis cepulw). — Forms black pustules on the leaves and 

 bulbs. Seedlings may be killed outright. 



Control. — Onions from sets or from seed started m soil free 

 from the di.sea.se S(>ld()m have the smut. Practice crop rotation. 

 Drill into the soil with the seed 100 pounds of sulfur and 50 

 pounds of air-slaked lime to the acre. 



