428 FIELD CROPS FOR THE COTTON-BELT 



easily recognized in a field of growing cane, the disease 

 being almost entirely on the inside of the stalk. From ex- 

 ternal appearance the cane may seem perfectly normal. 

 When the diseased stems are split open, irregularly dis- 

 tributed red streaks are noticed in the internal tissue. 

 Usually these red streaks or bands are found extending out 

 from the nodal region.^ A characteristic of this disease is 

 the occurrence of white spots surrounded by the red tissue. 



This disease damages the cane by causing a decrease in 

 its sugar content, and also by growing in the stages that 

 are to be used for planting, killing the eyes and thus causing 

 a poor stand. 



The treatment of the disease consists in destroying all 

 material in the field known to be diseased, and planting 

 seed-canes that are entirely free from the fimgus. In fact 

 little damage is done where perfectly healthy canes are 

 planted each season. , 



531. The rind disease. — This disease is caused by a 

 small fungus, Melanconium sacchari. The fruiting pus- 

 tules of this disease develop "underneath the epiderrnis 

 of the rind tissue" the spores being finally pushed out to 

 the surface of the stem. "As the spores are held together 

 with a mucilaginous substance, they ooze out in the form 

 of long black strings or hairs." ^ 



Xhe disease causes the cane leaves to dry up prema- 

 turely.- Finally the whole cane may become discolored 

 and brown. As the eyes are killed, diseased canes when 

 planted give little or no germination. Control measures 

 include the use of resistant varieties, the cleaning up of 

 fields, and the dipping of the seed-canes in bordeaux mix- 

 ture before planting. 



1 La. Agr. Exp. Sta., Bui. 120, p. 8. 

 ^ La. Agr. Exp. Sta., Bui. 120, p. 16. 



