VII 



BEET 235 



working from the tip to the base. Bordeaux is an 

 efficient remedy wherever it can be used with profit. 



Other Diseases. - - The 

 beets are also subject to the 

 attacks of the root disease 

 due to Rhizoctonia medi- 

 cagnis, DC., and Corticium 

 vaguni, B. & C. , var. solani, 

 Burt ; to the heart rot 

 caused by Phoma betae, 

 Frank ; to a rust caused 

 by Uromyces betae, (Pers.) 

 Kiihn ; to the scab caused by 

 Oospora scabies, Thaxter, 

 which also attacks pota- 

 toes ; to a downy mildew 

 which is caused by Pero- 

 norpora schachtii, Fckl. , 

 and to the nematode root 



galls. The scab and the FIG . 82> _ Beetleafaffectedwith leaf spot . 

 nematode root galls are Cercosporabetae. 



known to occur in the 



tropics, and the nature of the others is such that we 

 may expect them at any time. 



LETTUCE 



Lettuce is known in the temperate regions to suffer 

 from the " damping-oif " fungi, such as Corticium vagum, 

 B. & C., var. solani, Burt; the downy mildew caused 

 by Bremia lactucae, Keg. ; and the drop which is caused 

 by Sclerotinia libertiana, Fckl., and S. Fuckeliana, 

 De Bary. 



CELERY 



"Damping Off. "--This is due to the same organism 

 that attacks the potato and various other plants (see 

 page 29). It is very destructive in the seed beds and 

 may prove very destructive in the fields if the conditions 



