THE SUGAR-CAKE MOTH BORER. 53 
After the development of vacuum fumigation by Mr. E. R. 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 larvse 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. 
DESTKOYING OLD COKNSTALKS. 
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 Rico, except in one isolated locality, 
according to Mr. George N. Wolcott, formerly entomologist of the 
Insular Experiment Station of Porto Rico. 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 
