VEGETABLE AND FIELD CROPS 307 



to be transmitted by means of soil that has grown a sick 

 crop. FertiUzers which cause rapid growth favor the dis- 

 ease. 



The seed bed should be either new or well disinfected, and 

 it is advisable to destroy diseased seedlings in the bed if any 

 appear. Young plants should not be forced with strong 

 nitrogenous fertilizers and should be transplanted with 

 great care to avoid injuring them. It is well to top, worm, 

 and sucker the healthy and sick plants separately, on dif- 

 ferent days, with disinfection of the hands before passing 

 from the diseased to the healthy plants. 



Orobanche. — This is a true flowering plant, which draws 

 its nourishment from the roots of the tobacco plant to 

 which it is attached. The orobanche occurs in small 

 clusters, its stalks are from 1-4 dm. tall, and entirely de- 

 void of green color. 



They should be pulled and burned before they produce 

 seed. 



TOMATO 



Wilt, blight, bacillose {Bacillus solanacearum E. F. Smith). 

 — This disease of the tomato is widespread, especially in 

 the South, and prohibits the raising of tomatoes upon many 

 thousands of acres of land. It occurs especially in the 

 states south of Maryland, and has also been noted in New 

 Jersey, Delaware, Ohio, and Colorado. 



In this disease the leaves wilt, either singly or through- 

 out the entire plant at once ; growth stops and the plant 

 dies. The stem is at first dirty green, then brown, then 

 black. It soon shrivels, and the veins become brown and 

 show as narrow black lines, or in section as black dots. 



