CUCUMBER 



341 



should be waged on these pests, not only for the damage 

 which they may inflict by feeding, but also as transmitters 

 of these two diseases. Spraying is of no value for either 

 of the wilts. . Infected plants should be pulled up and 

 burned. 



Greenhouse Mosaic Disease has been studied by Selby 

 in Ohio. Concerning it he writes : "This disease is 

 analagous in character to the mosaic disease of tobacco 

 and tomatoes and to the yellows of the peach. It is due 

 to an oxidizing ferment in the leaves and is transmitted 

 like the tobacco mosaic disease, by touching first diseased 

 and then healthy plants. The fruitfulness of these varie- 

 gated yellow plants is very low, and it is best at all times, 

 upon the appearance of the disease, to remove the dis- 

 eased plants and destroy them/' 



Other diseases such as Leaf Spot, Pickle Spot, White 

 Pickle or Mosaic may appear on plants growing under 

 greenhouse conditions, but none of them should prove 



Fig. 120. Three grades of cucumbers. 



