THE sugar-cane moth borer. 5S 



After the development of vacuum fumigation by Mr. E. E. Sasscer, 

 of the Bureau of Entomology, a method which has proved highly 

 efficient in the destruction of insects in seed and cotton bales, it was 

 planned to fumigate cane by this system. It was a matter of general 

 surprise that larvae of the moth borer came out uninjured, even 

 when subjected to a strong fumigation (6 ounces sodium cyanid, 9 

 ounces sulphuric acid, and 18 ounces of water to 100 cubic feet) 

 for 1 hour, a vacuum of 25 inches being applied for 15 minutes and 

 a normal air pressure for the succeeding 45 minutes, the combination 

 of reduced air pressure followed by normal pressure having been 

 found very satisfactory for most species. 



DESTROYING OLD CORNSTALKS. 



Some sugar planters believe that if it were not for the growing 

 of corn on the plantations there might be little damage from the 

 moth borer in sugar cane. They reason that the borer finds an 

 acceptable food plant in corn before the sugar-cane plants are large, 

 and that if corn were eliminated the - emerging moths in the spring 

 presumably would die. 



Careful observations, however, show that the young cane plants 

 are attacked as early as corn in the spring, if not before. In fact, 

 the authors have always found borers in cane before they have 

 observed them in corn. It is true that the moths emerge from the 

 cornstalks in summer and fly to cane fields to deposit their eggs, the 

 dry corn plants no longer being attractive. But if there were no corn 

 the borers could, and many of them do, reach maturity just as easily 

 in sugar cane. 



Corn is not grown in Porto Eico, except in one isolated locality, 

 according to Mr. George N. Wolcott, formerly entomologist of the 

 Insular Experiment Station of Porto Eico. Yet a very high infesta- 

 tion is often found in sugar cane. 



It is probable that the elimination of cornfields from Louisiana 

 sugar plantations could have little or no effect on the numbers of 

 borers, but if the cornstalks could be destroyed before the borer 

 moths leave them a large number might be killed and the subsequent 

 infestation reduced. Borers have not been found in the dry stalks 

 at harvest, however, and the destruction of the stalks earlier than 

 midsummer would be impracticable, unless a specially early-maturing 

 variety of corn should be developed. The suggestion has been made 

 that the cornstalks be destroyed during the winter; but the moths 

 leave them many months before cold weather. 



In this connection it is worth noting that very late corn is often 

 ruined by the ravages of the larvse, the moths from the earlier corn 



