WINTER BLIGHT OF TOMATO. 183 



ate of copper, and fresh seedlings were set in it ; but 

 these plants also contracted the disease. Just before 

 this last treatment was given, a lo-inch pot was filled 

 from the soil in the box, and a seedling from the same 

 lot as those placed in the box was planted in it. The 

 pot was set in the tomato house. This plant showed the 

 disease in less than three weeks. The question at once 

 arises if the disease was not communicated through the 

 air from infected plants, rather than through the soil. 

 This I cannot answer, but it is certain that the disease 

 travels from plant to plant which stand in separate 

 boxes, and whose tops do not touch. Through what 

 distance this transfer can take place I do not know. 

 We observed it to have occurred through a distance of 

 2 or 3 feet, but a plant which stood 15 feet from dis- 

 eased plants, but separated from them by a glass parti- 

 tion in which two doors stood open, did not take the 

 blight. 



All our experiments, therefore, simply lead us to the 

 conclusion that the best treatment for this winter blight 

 is to remove all diseased plants at once, and if it be- 

 comes serious to remove all the plants and soil in the 

 house and start anew. They emphasize the importance 

 of starting with new plants and fresh soil every fall. 

 And all our experience has shown that the disease is 

 fatal to success in tomato forcing, for we lost our crop 

 in an endeavor to treat it. Since clearing our houses 

 thoroughly of this infection, we have never had it again. 



