Family Gramincae 251 



sweet com but three diseases need concern the 

 trucker. 



Bacterial Wilt 



Caused by Pseudomonas Steward Erw. Sm. 



Bacterial wilt is perhaps one of the most serious 

 diseases of sweet com. The trouble is very prevalent 

 in Long Island, New York, where it was first studied 

 by Stewart.' It is also prevalent in New Jersey, 

 Maryland, West Virginia, Ohio, Iowa, Illinois, and 

 probably many other States. 



Symptoms. Bacterial wilt has been carefully 

 studied by Dr. Erwin F. Smith, " who finds that the 

 symptoms of this disease are very distinctive. The 

 first mark on good sized plants is a drying out and 

 whitening of the tassel, giving the top of the plant 

 a peculiar whitish appearance. Another sign is 

 a dwarfing of the plant, followed by a drjnng of the 

 basal leaves which gradually works upwards (fig. 

 45 a) . The affected leaf dies from the tip downwards 

 or from the margin inwards. The disease often 

 attacks younjg plants and even seedlings, in which 

 case they dry and die out at an early stage. If an 

 infected plant is cut across the stan, we find a yellow 

 slime oozing out from the bundles; this slime is 

 teeming with the bacteria. In cutting through a 



' Stewart, P. G., New York (Geneva) Agr. Expt. Sta. Bui. 130 : 



424-439. 1897- 



^ Smith, E. P., Bacteria in Relation to Plant Disease, 3 : 89-174, 

 Washington, D. C. 



