86 MELON CULTURE 



discovery, it has spread over a wide territory and 

 has made its presence known in more than one wa- 

 termelon field. As it is supposed to have several 

 host plants, namely, watermelon, cotton, and cow- 

 pea, it is capable of being spread wherever any of 

 these plants are grown, and that means over the 

 greater portion of the United States. Ten years 

 ago it was confined to a somewhat limited area, so 

 far as its effect upon the watermelon crop was con- 

 cerned, but now it is found spread over a large por- 

 tion of the melon-growing territory in the middle 

 West and southern states. 



It is not especially influenced one way or the other 

 by climatic changes. In fact, it seems to thrive as 

 well in a winter temperature of 15 or 20 degrees be- 

 low zero as it does in localities where the tempera- 

 ture scarcely ever reaches the freezing point. The 

 fungus remains in the soil for an indefinite period, 

 and is ready to germinate and grow whenever the 

 proper host plant presents itself and the weather 

 conditions are favorable. 



The effect on the watermelon is similar to that of 

 the bacterial wilt on the muskmelon — a wilting of 

 the leaves and drying up of the entire plant, as 

 though the water supply had been suddenly cut off. 

 And, indeed, this is just what happens, as the fun- 

 gus finds an entrance into the plant through the 

 root system, and as it develops it clogs up the ducts, 

 thus preventing the moisture, which is taken up by 

 the roots, from reaching the foliage. This can be 

 readily seen by examining a cross-section of the 

 stem near the roots under a microscope The in- 

 fected part will also show a dark discoloration not 

 found in a healthy plant. 



