Family Cucurbitaceae 243 



mind that watermelon leaves are very tender and 

 hence susceptible to injury. Recent experiments by 

 the writer have shown that a very weak Bordeaux 

 with a large excess of lime should be used in order to 

 prevent the burning of the foliage. Where this pre- 

 caution is overlooked, a greater injury will result 

 from the use of the fungicide than from the disease 

 itself (rig. 44 b). A Bordeaux made up of three 

 pounds of copper sulphate, eight pounds of lime, and 

 fifty gallons of water, to which is added one pound 

 of powdered arsenate of lead, will answer the 

 purpose well. The lead arsenate in this case is 

 used against various caterpillars which often feed 

 on the leaves of the plants. Paris green should 

 not be used because of its tendency to burn the 

 foliage. 

 Cercospora Leaf Spot, see Cantaloupe, p. 224. 



Cercospora Leaf Spot 



Caused by Cercospora citrullina Cke. 



This form of leaf spot is induced by a species of 

 Cercospora different from that which attacks canta- 

 loupes. The trouble usually appears on the oldest 

 leaves as circular spots bordered by a dark brown 

 or purplish zone beyond which is an area of yellow. 

 The mature spots have gray centers. This form of 

 leaf spot is prevalent on watermelons in Texas. It 

 may be controlled by spraying in the same way as 

 recommended for anthracnose. 



