EXPERIMENT STATION BULLETINS. 275 



and having pale yellow or amber colored crusts over the affected areas. This 

 crust is due to the accumulation of myriads of amber colored bacteria which have 

 formed a layer over the broken down tissue. After a time the pod rots and the 

 beans are worthless. 



Warm, wet weather seems to favor the disease for the germs grow best under 

 these conditions and the beans at the same time produce more succulent growths 

 which are more readily attacked. Rain and dew are doubtless agents in spread- 

 ing the germs from one part of the plant to another by washing them from old 

 lesions onto unaffected parts. Insects play an important part in disseminating 

 the trouble, consequently any measures which tend to check these pests will 

 aid in controlling bacteriosis. The distribution of the disease is further effected 

 by dead vines and leaves carried on the wind; by the soil and through the seed. 

 New land which has never grown beans seems to be freer from the disease than 

 old and should always be used when available. 



The seed used in planting should be selected by hand and all the lighter ones 

 discarded for Gain* reports that anthracnosed seeds are less dense than sound 

 ones. As yet no satisfactory method has been found which can be recommended 

 for treating the seed to destroy the casual microbe which does not lower the 

 viability of the seed. 



Inasmuch as the germs of bacteriosis work on the outside of the plant, it is 

 possible to reach them with a fungicide and spraying with Bordeaux mixture* 

 upon two and three inch plants followed by the same ten days later and again 

 after blossomingt Dr. Halstead uses a Bordeaux mixture of the following 

 strength: Copper sulphate, 6 lbs.; lime, 4 lbs.; water, 60 gals. 



Variety tests conducted by the New Jersey Experiment Station during the 

 three years 1897-1899 with Green Flageolet, Currie's Rust-proof, Early Mohawk, 

 Golden Wax, Extra Early Refugee and Saddleback Wax showed the Green 

 Flageolet, the most susceptible, and the Early Refugee the least. 



BLACK ROT OF CABBAGE. 



The black rot of cabbage is to the truck producer what pear blight is to the 

 fruit grower; in fact, it may be considered far worse, for on the one hand there 

 is only the loss of the crop while on the other not only is the cabbage destroyed 

 but in addition the soil on which it has been grown is so inoculated that it Is 

 practically useless to attempt to raise the same crop on the same field with any 

 degree of success for a number of years. 



Bacterial examination of diseased plants has shown the sickness to be due to 

 a kind of germ.i The disease is by no means confined to the cabbage but attacks 

 other cruciferous plants such as cauliflower, collards, kohl rabbi, kale, brussels 

 sprouts and broccoli. It has also been reported as occurring in turnips, ruta- 

 bagas, wild radish and mustard. It is widely distributed in the United States, 

 having been found most prevalent east of the Mississippi River. In 1891 Prof. 

 W. Paddock reported it from Colorado. Previous to 1899 we do not hear of the 

 black rot in Europe but the investigations of Harding,§ confirmed by foreign 

 workers, show the disease to be wide spread and of long standing. England, 

 Holland, Denmark, Austria and Switzerland are mentioned as constant sufferers 

 from the malady. This is peculiarly interesting, since a few years back a great 

 deal of our cabbage seed was imported from Holland and Denmark. The com- 

 paratively recent discovery of the infection in Europe is probably due to the 

 better methods of diagnosing the disease than formerly rather than to recent 

 appearance of the trouble. Cabbage growers of Europe have observed it for 

 many years, it seems, but they were accustomed to associate the cabbage worm 

 with the rot rather than the true bacterial cause. 



The disease can be recognized by the dwarfed, one-sided growth of the plants and 

 in some cases, failure to produce heads. Sometimes the head will rot and fall off 



* Bulletin 151 N. J. Exp. Sta. 

 t Bulletin 121 Ohio Exp. Station. 

 t Pseudomonas campe.stres (Pannuel) Smith. 

 i Cent F. Bakt. II. Ab. Bd. VI— 305-31.3. (1900.) 



