620 SOUTHERN FIELD CROPS 



The Southern grass-worm (Laphygma frugiperdn) is some- 

 times troublesome in Louisiana after overflows. Treatment 

 consists in attaching a light piece of timber to the cultivating 

 implement in such a way as to jar the cane, which causes the 

 caterpillars to fall to the ground, where they are covered with 

 soil by the cultivator. Dusting plants \^dth one part Paris green 

 to five parts of slacked lime is also recommended by Stubbs. 



The sugar-cane leaf-hopper occurs in Hawaii, having been 

 accidentally introduced in seed canes from Australia. The 

 method of combating it consists in the importation of its insect 

 enemies or parasites. This leaf-hopper is not known in the 

 United States. 



507. Diseases. — Red cane, a discoloration of the in- 

 terior of the stem following cuts or bruises, is harmful if 

 such injured canes are planted. 



There are several serious fungous and bacterial diseases 

 of sugar-cane occurring in tropical countries. Among 

 the means of escaping many of these are the selection of 

 varieties that show the greatest resistance to these 

 diseases. 



Root disease. — This is due to a fungus (Marismiua sacchari), 

 wliich may live from season to season in the soil or in the dead 

 and decaying parts of the diseased cane plants. The disease 

 may be shown above ground by the formation of a white, mold- 

 like growth on the lower lea^-es. The plants appear as if suffering 

 from severe drought, due to the loss of many of the small roots, 

 killed by this disease. Pre\-enti\'e measures consist in burning 

 the cane litter or diseased areas and planting canes free from 

 disease. It is best for the canes for planting to be grown in a 

 special seed field, the " seed cane " for which has ei+her been 

 carefully examined, or perhaps disinfected (La. Expr. Sta., Bui. 

 100). Any methods of improving conditions for the growth of 

 cane, as drainage and good cultivation, minimize the injury from 

 this disease; 



