WILT OF CUCURBITS. 



21 I 



Some years ago near Albany, New York, it did much damage to fields of cucumbers according 

 to John E. W. Tracy of the U. S. Department of Agriculture, who also saw it near Rochester. 



This disease was common in squashes and cucumbers at Hubbardston, Michigan, in 

 1895 and subsequently. 



On August 20, 1897, I saw near Saginaw, Michigan, two fields of cucumbers in which 

 the disease was present. There were vines in all stages of wilt from those just beginning 

 to be affected to those which were dried up. When I made cross-sections of the stems 

 toward the root and touched the cut end with my finger the bacilli strung out in the char- 

 acteristic way in delicate sticky threads. On showing the plants to a cucumber-grower he 

 said he was familiar with the disease but did not know its cause. 



During the same month I saw this wilt in cucumbers and squashes at Grand Rapids, 

 Michigan. 



In 1898, Mr. S. S. Bailey, of Grand Rapids, Michigan, lost many of his squashes by 

 this disease. 



It was seen by the writer in muskmelons at Racine, Wisconsin, in 1897. It has been 

 reported by Prof. Pammel from Iowa. 



Mr. Ragan, the horticulturist tells me he has seen it in Indiana. 



Fig. 51.* 



Specimens of cucumber attacked by this disease were received by me from Morrison, 

 111., in 1899. The slime was so sticky that when touched with the finger, it strung out from 

 the end of the cut stem over 76 cm. (30.5 inches). It also occurs in the vicinity of St. 

 Joseph, Mo. 



Mr. Barlow has observed it at Guelph, Ontario, in a variety of cucurbits. 



SIGNS OF THE DISEASE. 



This disease is readily detected owing to the striking nature of the phenomena. The 

 wilt is first local, affecting certain individual leaves (plate 1, fig. 1 and various text figures), 

 but soon becomes general, involving the foliage of the entire plant (plates 13 and 14). Asso- 

 ciated with the wilt we always find a white ooze exuding from the vascular bundles of leaves 

 or stems on cross-section (fig. 51), and this exudate is usually viscid. The only other dis- 

 eases of cucurbits liable to be confounded with this are: (1) The more or less sudden wilt 

 due to the presence of the larvae of the squash-vine-borer {Aegeria cucurbitae) in the base 



*Fig. 51. Cross-sections of cucumber-stems, showing bacterial ooze (Bacillus trachciphilus) from the bundles. 

 Plants from New York. Photographed Aug. 1 1, 1904. Enlarged about ten times. 



