THE SUGAR-CANE MOTH BORER. 33 



Because the species is so prolific, it is easily possible for a very 

 few borers which remain alive in the spring to cause a high infesta- 

 tion over a whole plantation by the following grinding season. 



NATURAL DISSEMINATION. 



The moth borer has not been found to extend noticeably the limits 

 of the area infested by it, as the cotton boll weevil does. The insect 

 has never been found at Bunkie, La., though it has been observed at 

 Melville, some 30 miles southeast, since 1914, and has probably been 

 there for a much longer time. 



ARTIFICIAL DISSEMINATION. 



It is apparent that the infestation of new territory is caused princi- 

 pally through shipments of sugar cane, both for grinding and plant- 

 ing. The mature canes, if infested, contain larvae or pupae or both, 

 and if left in a freight car on a railway siding, or if planted and 

 imperfectly covered, the resulting moths can easily emerge. It is 

 then an easy matter for the species to become established on such food 

 plants as may be available at the time of year, and the infestation of 

 adjacent cane fields may be expected within the next few years. 



Infested seed cane was planted about 1909 above Baton Rouge on 

 property which had previously been devoted to cotton farming and 

 undoubtedly was not infested by the moth borer. In 1914 practically 

 every stalk of cane was bored. 



Introduction of new varieties of sugar cane should be left to experi- 

 ment stations, and the cuttings should be subjected to special treat- 

 ment and inspection (see " Immersion and fumigation," p. 49). 



If cane is needed for planting or grinding by persons outside the 

 infested area, great care should be taken to secure uninfested cane. 

 Freight cars used for hauling cane may contain infested scraps which 

 should be collected and destroyed at frequent intervals. 



HIBERNATION. 



STAGE OF INSECT THAT HIBERNATES. 



The moth borer passes the winter in the larva stage. As fall ap- 

 proaches some of the larvae go into hibernation, while others enter 

 the pupa stage and emerge shortly as moths. There is nothing to 

 indicate which of these two classes will hibernate and which will 

 become moths. During the summer of 1913 some of the larvae from 

 eggs laid as early as August 13 went into hibernation, while others 

 from the same mass of eggs completed their development as usual. 

 Other larvae from eggs laid August 18 and September 8, 22, and 27 

 died or hibernated, but larvae from eggs laid September 1 and 18 

 completed their development and emerged in October and November. 

 83363°— 19— Bull. 746 3 



