1901».J PUBLIC DOCUMENT — No. 31. 53 



been planted a few mouths showed practically every plant af- 

 fected and about 85 per cent, already dead. Those still alive 

 were not over 2 or 3 inches in height. 



To the west of this plot !/> acre was planted to Golden Self- 

 blanching, and although the plants had been set out for only 

 three weeks the disease was quite prevalent among them. The 

 plants adjoining the plots affected in 1907 were very much 

 more severely affected than those further away. On a slope 

 sonic distance from this plot about 2 acres w^ere planted to 

 Golden Self-blanching, Albany Market and Boston Market, and 

 this field contained numerous affected plants, although the 

 disease here was not so marked. Golden Self-blanching seemed 

 to be affected most severely, while Boston Market was troubled 

 the least. On a plot further removed from the original source 

 of infection % acre of Golden Self-blanching was planted. This 

 appeared to be entirely free from the disease. The seed used 

 was obtained from two Boston firms, but no difference in sus- 

 ceptibility was shown. 



The early plants, which Avere most seriously affected, were 

 raised in sterilized soil in hotbeds, and no disease made its ap- 

 pearance among the few plants which were left in this ster- 

 ilized soil, which would seem to indicate that infection did not 

 come from that source. The i)lants taken from seed beds in 

 fhe open ground, in which unsterilized soil was used, showed a 

 little of the disease, and the j^lants left in these seed beds sub- 

 sequently became infected. 



The soil in which this celery grew had up to this time pro- 

 duced good crops. It had received heavy dressings of horse 

 manure, and commercial fertilizers had been applied freely. 



Observations made of the affected plants in both seasons show 

 that the trouble is caused by bacteria, and little difficulty is 

 experienced in isolating them. The symptoms of this disease 

 do not coincide with those of any previously described. It 

 seems to have originated on one piece of land on this farm and 

 spread from this to the different fields, and from the fact that 

 no disease occurred on the plants loft in sterilized soil it would 

 seem that the germs must be in the field. 



A study is now l)oing made of this trouble, both in the lab- 

 oratory and in the field. 



