BACTERIAL DISEASES OF PLANTS 263 



plants from the seed bed is important. Warm, moist 

 weather is favorable to the development of the malady. 

 Duggar advises soaking the seed for twenty minutes in 

 formalin solution, one part to two hundred parts water. 



OTHER BACTERIAL DISEASES 



The Bacteriosis or Blight of the Bean and related plants 

 is another destructive disease. It affects especially the 

 pods, producing soft spots with a characteristic water- 

 soaked appearance. More rarely it attacks the stems and 

 leaves. Apparently the disease may be started through 

 infected seeds, so that care to select seeds from blight-free 

 fields is desirable. 



The Bacteriosis of melons, cucumbers, and other vines 

 is still another destructive malady. The bacteria develop 

 in enormous numbers in the water channels of the plants, 

 thus preventing water from reaching the leaves, and caus- 

 ing the sudden wilting of the latter. Flea beetles, striped 

 beetles, and other insects help to carry the microbes from 

 plant to plant. 



Corn and celery are both subject to bacterial diseases, 

 and cotton bolls are attacked by microbes that cause the 

 Cotton Boll Rot. Potatoes, tomatoes, and eggplants are 

 the victims of another bacterium that causes injury to 

 leaves and tubers or fruits. 



OBSERVATIONS FOR PUPILS 

 PEAR BLIGHT 



1. Have you ever seen pear trees injured by this disease? 



2. How did it show itself ? 



3. Have you seen blighted apple branches? 



4. Read this reference : 



Pear Blight : Its Cause and Prevention, Yearbook Reprint 500. 



