402 Report of the Mycologist of the 



Island. Certain varieties have been much more severely attacked 

 than have others, but the disease has been widespread on Long 

 Island and, in several instances, destructive, particularly in ^e 

 season of 1897. Occasionally, an entire crop has been ruined and 

 losses of from 20 to 40 per cent have been frequent; but in the 

 majority of cases the loss has been so slight as to pass unnoticed 

 by the farmer, although one familiar with the disease could 

 readily detect it In almost any field of early sweet corn on Long 

 Island during the past season. 



Although we had here to deal with a disease of considerable 

 economic importance, it soon became evident that it is an unde- 

 scribed disease caused by a species of bacterium which is prob- 

 ably unknown to science. Previous to the discovery of this dis- 

 ease, the only known bacterial disease of corn {Zea mays) was one 

 described by Burrill* in 1889. Burrill's disease affects field corn 

 and differs so widely from the disease under consideration that 

 there is no doubt that the two are entirely distinct. 



SYMPTOMS OF THE DISEASE. 



Some bacterial diseases of plants are very difficult to diagnose. 

 They have no characters by which they can be readily identified 

 without the aid of a compound microscope, and for some diseases 

 the revelations of the microscope must be supplemented by infor- 

 mation obtained from the study of cultures. Fortunately, this 

 disease of sweet corn has some distinguishing characters by 

 which it can be identified with certainty and without the aid of a 

 microscope. 



The affected plants wilt and dry up without any apparent 

 cause. This may occur at any stage of growth but it is most 

 likely to occur about the time of flowering. The past season it 

 was observed to be very prevalent as early as June 12, among 

 plants which were from eight to ten inches in height. The leaves 

 wilt and then gradually wither. The time which elapses between 

 the first appearance of the disease and the death of the plant 

 varies greatly. In some cases it may be no more than four days, 

 while in others it may occupy a month. Sometimes an affected 



•BurrUl, T. J. A Bacterial Disease of Corn. l\\. Agl. Exp. Sta. Bui. No. 6. 



