ISTew Yokk AGEicrLTUKAL Experiment Station. 171 



"Wlien the rot is confined to the outermost fleshy scale, as is 

 frequently the case, the alTected bulbs are called " slippery onions." 

 Some of these are to be found in any season, but they are rarely 

 so abundant as to cause material loss. 



Microscopic examination of the rotten tissue shows entire ab- 

 sence of funa'i, but there are swarms of a medium-sized motile 

 bacillus which is without doubt the immediate cause of the rot. 



When the rot commences at the bottom of the bulb the whole 

 lower part is soft and eventually the entire onion becomes in- 

 volved. The rot spreads upward through all of the scales simul- 

 taneously. Bulbs so affected show a profuse growth of Fusarium 

 about the base and the rotten tissue is filled with the Fusarium 

 hyphse mingled "with the previously mentioned bacillus. Although 

 the presence of the bacillus is sufficient to account for this base 

 rot it seems probable that the Fusarium aids materially and in 

 some cases it may be the primary cause. 



By inquiry among onion growers it was learned that there is in 

 nearly every season a small amount of loss from rot which usually 

 appears in the form of " sHppery onions," although both the center 

 rot and the base rot have long have been known. The note- 

 worthy fact in connection with the rot in 1898 is the unusually 

 large amount of center rot. 



The rot was noticed by farmers when the crop was harvested in 

 August, but the full extent of the trouble Avas not realized until a 

 month later when the crop was sorted for mai"ket. At first it was 

 attributed to injury from bail which fell on July 30; but later the 

 hail theory was rendered untenable by the discovery that there 

 was considerable rot in fields which had not been struck by the 

 hail. Probably, the wind accompanying the hailstorm was a much 

 more important factor in the rot. In nearly all of the onion fields 

 the tops were much broken by the wind. 



Among stored onions kept reasonably dry the rot progresses very 

 slowly, but wet onions rot rapidly, especially if the temperature 

 is high. 



