BLACK ROT OP CRUCIFERIOUS PLANTS. 331 



The black rot in cauliflower caused a loss of $400 per acre to a planter at Beeville, 

 Texas, in the winter of 1902, according to his statement to me. Diseased plants were 

 received from him, the organism was plated out on agar, subcultures were made on potato, 

 and then it was re-inoculated into cauliflowers, which became diseased with the typical 

 black rot. 



Similar statements respecting losses have been received from many other places (see 

 p. 328). Not infrequently in various parts of the country entire fields have been destroyed so 

 that not a single plant was harvested. Russell has published a very interesting figure of 

 such a field. At the present time the disease is destructive to a greater or less extent, 

 according to the season, on Long Island, in Western New York, and in parts of Ohio, 

 Illinois, Michigan, Wisconsin, and Texas. The disease has come into general notice in 

 this country only recently, but the losses from it in the vicinity of Racine, Wisconsin, were 

 estimated for me by good observers 14 years ago at not far from $150,000. The disease is 

 also said to be so prevalent in parts of New York that extinction of the industry is threat- 

 ened. The writer estimates the losses on Long Island during the last 12 years at upward 

 of $250,000. Probably the total loss from this disease in the United States since its first 

 appearance has been not less than $800,000. 



Hecke reports this disease to be common in Austria on a variety of crucifers. The 

 loss on a kohlrabi field in Southern Austria, which furnished the first material for his studies, 

 was very great, in fact almost complete, since it was impossible to use the black veined 

 tissues for preserving. Van Hall's correspondent in North Holland says that the disease 

 has existed for several years, first attacking Utrecht red cabbage but at present attacking 

 all varieties and even cauliflower. The damage is worst on the red cabbage. The disease 

 is so dreaded that many fear the culture of cabbage will have to be given up. Many hec- 

 tares of cabbage are diseased this year (1900) so that from seven-eighths to nine-tenths of 

 the harvest will be lost. 



In the United States cabbages are often stored in large quantities for the spring market, 

 and the black rot frequently continues in such plants, particularly in the warmer parts of 

 the houses usually associated with soft rots. 



According to Russell a quarter of the stored crop of cabbage was lost at Racine, Wis- 

 consin, in the winter of 1896-1897 by the development of this disease in the stock. When 

 taken out such cabbage heads are often sound externally although badly rotted within. 



HISTORY. 



Carman (1891-1892) appears to have been the first to comment on this disease. He saw 

 what we may infer to have been this disease in July, 1 889, at Lexington, Kentucky, but did not 

 make out its etiology. From the diseased cabbages two organisms were isolated, anon-motile 

 white and a motile yellow. In most of the cabbages the yellow form was the commoner one. 

 "The size and behavior of this [yellow] species leads me to think it a form of Bacterium 

 tenno." The two species were not described. A quick decay [soft rot] was obtained by 

 transfer of some of the diseased material to the interior of healthy cabbages, but pure cul- 

 ture inoculations were not successful. Further opportunity for studying the disease did 

 not present itself and the writer leaves the subject with the following remark : 



"Whether the disease is induced primarily by the attacks of bacteria, or by hot, damp weather, 

 the work thus far done does not show satisfactorily. From the facts in my possession it appears to 

 me probable that neither alone will cause the disease ; that it is only during periods of high tempera- 

 ture and excessive rainfall that the organisms are able to invade and break down the tissues of plants." 



Pammel (1893-1895) was the first to demonstrate the infectious nature of the disease. 

 He isolated a yellow bacterium from rutabagas and determined it to be the cause of the 

 disease by means of pure culture inoculations. 



