244 Diseases of Truck Crops 



Vine Wilt or Yellows 



Caused by Fusarium niveum Ew. Sm.; Fusarium 

 citruUi Taub.'; Fusarium Poolensis Taub.' 



Failtire of the watermelon crop in many of the 

 Southern States may be safely attributed to wilt. 

 There is no other watermelon disease that is so diffi- 

 cult to control. The reason is obvious. The causa- 

 tive fungi live in the soil as semi-saprophytes. The 

 longer watermelons are grown on that soil, the worse 

 the disease becomes. In severe cases the crop may 

 be a total failure, or the loss run as high as fifty per 

 cent, of the crop. 



Symptoms. There is no outside spotting nor are 

 there any lesions to indicate the presence of wilt. 

 The source of the trouble is confined entirely to the 

 interior of the roots and stems. The leaves of an 

 affected plant suddenly droop; this is followed by a 

 rapid wilting of all the vines in that hill (fig. 44 a) 

 from which they never revive. The wilting is more 

 intensified dtiring a warm dry spell. Occasionally 

 only one or two vines in the hiU wilt and die while 

 others in the same hill remain alive for some time 

 before succumbing to the disease. In p ullin g out a 

 plant that has recently died, its roots are found to be 

 sound with the exception of a dull yellowish color 

 which the exterior exhibits. In splitting open a vine 



' From unpublished data by the writer, the organism was carried 

 as Fusarium No. 106. 



' The organism was carried as Fusarium No. 1 16. 



