SUGAR-CANE HARVESTING, ENEMIES 427 



seed-canes should be used. Crop rotation is also advisable 

 but as sorghum, Johnson-grass, and corn are also attacked, 

 the task of starving the insects is often difficult. 



528. The southern grass worm (Laphygma frugiperda) 

 often does considerable damage to sugar-cane. It can be 

 controlled by spraying the crop with arsenic solution, made 

 by mixing three pounds of lead arsenate paste or one pound 

 of zinc arsenite powder to fifty gallons of water, or by 

 dusting the plants with the latter, using air-slaked lime as 

 a filler. 



Another means of destroying these worms is that of 

 attaching a light piece of timber to the cultivator so as to 

 jar the cane, causing the worms to fall to the ground where 

 they are covered with soil by the cultivator. 



FUNGOUS DISEASES 



529. Origin. It is only within recent years that 

 fungous diseases have caused serious injury to the sugar- 

 cane of the southern United States. At least one disease, 

 the sugar-cane root-rot, has probably been present in the 

 sugar-belt of Louisiana for many years, but has caused 

 serious injury only in abnormal years. Recently other 

 diseases, notably the red-rot, the rind disease and the 

 pineapple disease have been found to be more or less 

 prevalent in various parts of Louisiana, the red-rot being 

 also prevalent in parts of the coastal pine-belt. As these 

 are fungous diseases to which sugar-cane is subject in its 

 native home, it is quite likely that they have been intro- 

 duced on seed-canes from the tropics. The interchange 

 of seed among the different planters in this country has 

 served to increase the spread of these diseases. 



530. Red-rot of sugar-cane. This disease is caused 

 by a small fungus, Colletotrichum falcatum. It is not 



