Family Cucurbitaceae 239 



more abundant on the older leaves, or even on the 

 nearly mature melon fruit. Although the mold seems 

 to grow superficially on the outside of the affected 

 parts, the result is a general suffocation, since sun- 

 light and free circulation of air are interfered with. 

 Sooty mold undoubtedly grows on the sweetish ex- 

 creta of plant lice, and is severest during seasons of 

 Aphis epidemics. Spraying with "Black Leaf 40" 

 to control Aphis gossypii will also control sooty mold. 

 The fungus Capnodium apparently does not derive 

 any nourishment from the watermelon, but from the 

 honey excreted by plant lice. 

 Mycosphaerella Wilt, see Cantaloupe, p. 222. 



Stem End Rot 



Caused by Diplodia tubericola (E. and E.) Taub. 



This disease was first studied by Meier 1 who found 

 the trouble confined mostly to watermelons in transit. 

 Many carloads when reaching their destination 

 showed a loss from it of 75% to 95%. 



Symptoms. The first indication of the rot is a 

 browning and shriveling of the stem end of the fruit 

 (fig. 42 a). Rotting begins at the point of attach- 

 ment of the melon to the stem of the plant. The 

 flesh of the affected melon blackens, softens, and 

 becomes watersoaked and then slimy. Such melons 

 when left to themselves become black, wrinkled, and 

 mummified. Infection undoubtedly must take place 



1 Meier, F.C., U. S. Dept. of Agr., Journal ofAgr. Research, 6 : 149- 

 152, 1916. 



