Celery 127 



an acre should be 400 to 600 dozen bunches of 3 or more stalks 

 each, if the distance of planting is 3 ft. by 6 in. 



Late blight or celebt (Septoria p^troselini). — Irregular 

 brownish spots containing small black fruiting bodies are pro- 

 duced on leaves and leaf-stalks. Frequently the spots unite, 

 causing the entire leaf to become dry and papery. Bacterial 

 BLIGHT. — Lesions differ from those of late blight in that the 

 spots are smaller, more regular in outline, darker brown in 

 color and have no black fruiting bodies scattered over them. 

 Cercospora blight (Cercospora apii). — Characteristic ashen 

 gray spots develop. Later the entire leaf may become some- 

 what yellowed and ashen gray and velvety. Control: All of 

 the above blights are controlled by thorough spraying with 

 bordeaux mixture 5-5-50. If the disease Is present in the 

 seed-bed one or more applications there is advisable. Field 

 spraying with two nozzles to the row, the two being placed 

 some distance apart and at such an angle that the two sprays 

 overlap at the top of the row and thoroughly cover the sides, 

 is advisable. Applications should begin about three weeks 

 after transplanting and should continue at about weekly inter- 

 vals, depending somewhat on weather conditions, till blanch- 

 ing time. 



Storage rot (Sclerotinia Uhertiana). — Frequently plants of 

 celery in storage become water-soaked in appearance, and on 

 this softened tissue white felts of mycelium containing hard 

 black fungous bodies develop. Control: The introduction of 

 wounded plants or those showing beginning of decay, is to 

 be avoided. The maintenance of proper storage conditions is 

 imperative. 



Carrot eust-flt (Psila rosw). — A slender straw-colored 

 maggot, 3^ in. long when mature, that eats off and destroys 

 the fibrous roots of young celery plants. A second brood 

 appears in late summer and bores in the taproot. No prac- 

 ticable method of control is known. 



Black swallow-tail butterfly {Papilio polyxenes). — A 

 beautiful green caterpillar about 2 in. long, each segment with 



