THE BACTERIAL TOMATO BLIGHT 181 



bacterial blight of potatoes. The tissues of diseased 

 plants teem with bacterial germs, and no other form of 

 fungus is present at first. The malady has been studied 

 by Dr. B. D. Halsted, who has published a preliminary 

 account of it in Bulletin No. 19 of the Mississippi Ex- 

 periment Station. The presence of the disease is usu- 

 ally shown by the wilting of the younger leaves, especially 

 those at the ends of the stems, and the yellowing of the 

 older foliage. The stems themselves also become af- 

 fected, and when closely examined, are seen to have 

 numerous watery spots. A longitudinal section of such 



FIG. 77. VMOHTK.D TOMATO LEAVES. 



a stalk reveals a greenish, watery center, very different 

 from that of the healthy plant. 



There is a blight affecting squashes and melons that 

 seems to be the same disease as this, and also as the 

 potato blight already referred to. Consequently neither 

 of these crops should follow the other on the same land, in 

 case the disease has appeared. It is believed that the 

 soil becomes so contaminated with the germs that, in 

 case either of these crops follows the other, the injury 

 may appear again. In addition to proper rotations, the 

 burning of all diseased plants and rubbish in the field, 

 and spraying early with Bordeaux mixture, are recom- 

 mended as remedial measures. 



