128 Diseases of Truck Crops 



be controUed by deep fall plowing and crop rotation. 

 No hard and fast system of rotation can be laid down 

 for the trucker. He himself must be the best judge. 

 It seems that the conidia of the fungus are tmable to 

 Uve over winter. The parasite, however, winters 

 over as mycelium within the affected leaves. Deep 

 plowing, therefore, not only improves the land but 

 will also help to buiy the debris of infested leaves, 

 thereby removing the fungus as a source of infection 

 for the following year. Spraying will also help to 

 control leaf spot. The formula recommended is 4 

 pounds copper sulphate, 4 pounds fresh slaked lime, 

 to 50 gallons of water. To succeed in keeping the 

 disease in check, spraying must be carefully carried 

 out. The leaves should be thoroughly coated with 

 the mixture both from the upper and under sides. 

 Clean culture and constant cultivation will also check 

 leaf spot. This will tend to maintain the moisture 

 in the soil, at the same time preserving the vigor of 

 the plant. Any operation which tends to weaken the 

 plant will also favor infection. 



Root Rot 



Caused by Corticium vagum B'. and C. 



This disease is very prevalent in the United States, 

 attacking a large number of truck crops in which the 

 beet is included. It has been carefully studied by 

 Duggar and Stewart' and by others. It produces 



' Duggar, B. M., and Stewart, F. C, New York (Cornell) Agr. 

 Expt. Sta. Bui. 186 : 50-76, 1901. 



