UNITED STATES DEPARTMENT OF AGRICULTURE 



m BULLETIN No. 829 



at *5l 



jJ£r Contribution from the Bureau of Plant Industry W 



JZ&f^Cru WM. A. TAYLOR, Chief &&P"^fU 



Washington, D. C. 



PROFESSIONAL PAPER 



October 29, 1919 



THE MOSAIC DISEASE OF SUGAR CANE 

 AND OTHER GRASSES. 



By E. W. Brandes, 



Pathologist, Sugar-Plant Investigations; formerly Pathologist, Porto Rico Agricultural 

 Experiment Station, Mayaguez, P. R. 



CONTENTS. 



History of the disease 1 



Distribution in the United States 4 



Losses in the United States 7 



Primary symptoms 8 



Secondary symptoms 10 



Injuries resembling mosaic 12 



Varietal susceptibility 12 



Varieties attacked , 12 



Immune varieties 14 



Other hosts 15 



Nature of the disease 16 



Infection phenomena 16 



Transmission of mosaic in diseased seed 



pieces 18 



Nature of the disease— Continued. 



Transmission of the disease by carriers .... 18 



Soil relations .. 19 



Relation to disinfectants 20 



Relation to fertilizers 20 



Control 20 



Elimination by roguing 21 



Elimination by grinding all cane and secur- 

 ing clean seed 22 



Exclusion 22 



Eradication 23 



Elimination by planting immune varieties. 24 



HISTORY OF THE DISEASE. 



The mosaic disease of sugar cane, the presence of which has 

 recently been discovered in Louisiana and other Southern States, 

 is the malady that in epidemic form has occasioned severe losses in 

 parts of Porto Rico during the past four years. There it has been 

 variously called matizado, "mottlings;" rayas amarillas, "yellow- 

 stripe;" morida de perro, "clog bite;" la enfermadad de Arecibo, 

 "disease of Arecibo;" la enfermadad nueva, "new disease;" etc. 

 The disease was first noticed in Porto Rico about the middle of 

 1916. 



Starting from some point near Arecibo, on the north coast of 

 Porto Rico, it spread rapidly over the cane fields to the west, down 

 the west coast to the south coast, and up into the valleys and hills 



