134 Diseases of Truck Crops 



substance which is dissolved by the least contact 

 with rainwater or dew. The spores are then carried 

 about by the same agencies as mentioned for the or- 

 ganism of spinach anthracnose. 



BLACK MOLD 

 Caused by Cladosporium macrocarpum Preuss. 



This disease attacks the oldest leaves of the plant 

 in dark patches which are covered with numerous ir- 

 regular dark spore-bearing branches or conidiophores. 

 It is of little economic importance. 



LEAF SPOT 

 Caused by Heterosporium variabile Cke. 



This disease is very prevalent on winter spinach 

 in Eastern Virginia. It generally attacks plants 

 which have been weakened by downy mildew, or by 

 other diseases. Reed and Cooley, z who have studied 

 it carefully, find that indirectly it causes considerable 

 losses to the growers. It necessitates, for instance, 

 the trimming off of dead or diseased leaves, this 

 requiring extra labor and reducing the quantity of 

 marketable spinach. The disease is at its height 

 when the plants attain their maximum, beginning in 

 January and continuing until about March, the close 



1 Reed, H. L., and Cooley, J. S., Virginia Agr. Expt. Sta. Ann. 

 Rept. 1909 and 1910. 



