MOSAIC OF SUGAR CANE AND OTHER GRASSES. 7 



sugar cane. Concerning the probable time of the importation that 

 was responsible for the present wide distribution of mosaic in Amer- 

 ica, the survey has brought out the fact that the distribution of cut- 

 tings by the Louisiana Sugar Experiment Station in 1914 and prior 

 to that time has not resulted in. establishing the disease at the points 

 where such cane was received. Since 1914, however, every point 

 receiving seed from the station has become the center of a larger or 

 smaller infected area. The inference, of course, is that while the 

 disease may have been present at the station for a few years prior 

 to 1914, it had not become so widespread that every seed shipment 

 from there contained some infected cuttings. At the present time, 

 about 97 per cent of the cane plants at the station have the mosaic 

 disease. It is probable that private individuals have imported cane 

 with this disease, but such cane is not likely to be widely distributed, 

 and its spread, therefore, must depend upon natural agencies, a 

 much slower process. 



Without exception, every infested area in Georgia and Florida can 

 be directly traced to distributions of seed cane from the Sirup Field 

 Station at Cairo, Ga., since 1916, and the infection at this station 

 dates from the importation of a number of varieties from Audubon 

 Park in 1915. In nearly every instance where diseased cuttings 

 have been received from Cairo, it has resulted in secondary infection 

 of the surrounding native cane. 



The above is the brief and much condensed compendium of a large 

 amount of data collected during July, August, and September, 

 1919. It has made possible the recommendation of plans of attack 

 upon the mosaic disease, which vary slightly in the different cane 

 regions of the country, but all of which, if strictly adhered to by every 

 cane planter, will bring the disease under control. Its capacity for 

 rapid spread, as demonstrated in Georgia and Florida, means that 

 a lapse of one year will result in immeasurably complicating the 

 problem of ultimate eradication. 



LOSSES IN THE UNITED STATES. 



Since the mosaic disease had been unrecognized in this country until 

 the writer announced its presence in July of this year, no extensive 

 data have been accumulated to determine whether the losses caused 

 by it in the United States are comparable with those sustained in Porto 

 Rico. A few figures (Table II) have been obtained in Louisiana, 

 however, which indicate that we may expect a decrease in yield 

 almost equal to that in Porto Rico if the disease is permitted to 

 become as widespread here as it is in that country. Losses here are 

 held in check somewhat on account of frequent replanting. It has 

 been noticed that where infected sugar cane is allowed to ratoon over 

 a long period of years that losses due to the mosaic are more severe 



